I imagine the answer to this could be as varied as the magi engaging in the War, but I just can't really think of anything a magus might do during a War aside from seeing the other magus (possibly magically, since the Code's off) and opening fire. What kinds of tactics and strategies, if any, might be prevalent in Wizard War-ing?
It's a bit of an open ended question... Can you provide some details upon a possible situation?
You'll have direct confrontation and hiding and everything in the spectrum between those two...
Um... Gee, okay. I'll lay out a few boundaries, and see if that helps.
Let's say you had two magi, both specialists with a decade or three under their belts. One's specialty is pure Intellego, and they've got a bit below a 30 in it. The other one's a Creo Auram specialist, with both of those Arts being at or just below 20. Both magi have around 5-10 in their non-specialist Arts, and whatever non-Art skills you'd consider appropriate to a magus at that level of advancement. Assume that those Art scores are already factoring in Virtues like Puissance.
One magus grievously personally offended another in an attempt to provoke them into declaring War, and it worked. Now that the War has started, both magi actively and strongly seek the other's demise by the end of the conflict, though the hatred isn't quite strong enough for either to attempt a suicide attack to take the other out.
Would those boundaries give you enough to build a scenario off of? I understand the concept behind the War itself, but due to my own inexperience, I just can't imagine what they even do except for, like, try to wait each other out within their own safety bubbles (covenants), and the first one to lose patience and walk up to the other covenant and shout "come out and fight, you coward!" gets fried with lightning/mind controlled/whatever.
Hopefully the one that provoked the war was smart enough to prepare for it before war was declared. Preparation is key here. A magus with a season to cook up something new has a huge advantage, once war has been declared there isn't enough time to research anything new, but a prepared magus is a deadly magus.
All other thing being equal I would rather be the Intelligo expert here, knowledge is power.
Also, there is nothing that says the war has to be completed using magic, a knife in the back from a mundane assassin can ruin anyone's day.
Hermetic Projects (I think it's that book) has the section on Intangible Assassins which deals specifically with the aspects of using spells remotely on a target, which would be a very common tactic in a wizards war. It is one of the must read chapters in the Ars sourcebooks imo.
There has also been a few threads previously talking about prep for wizards war too which was also a good read here.
Before you pick an intentional War, the ideal situation is to spend a season fixing an Arcane Connection to your target. Then snipe him from afar the moment the War begins.
Which is why the default strategy for defensive wizard's war is "give all your stuff to your Soldales, then take that trip into the Twilight Void you've been putting off, for a month" - that protects all your property, and keeps you from getting hit via an Arcane Connection.
That's pretty cowardly.
The default strategy should be "kill or disable your enemy before he kills or disables you".
It also doesn't solve anything, because your enemy can simply declare WW again. Meanwhile, you are accumulating Warping to flee into Twilight.
Of course, defensive warring relies heavily on having a fellow magus you can truly trust nearby, because whoever you pass your stuff to before going into Twilight is under no legal obligation to return any of it when you're back. You could declare War and take it back, but... Well, that option is a bit counter to what a defensive warrer does.
On the other hand, the attacking magus probably can't spam War at you either. The Tribunal might be sympathetic to him if the defensive magus hands off his stuff, disappears, and comes back after to re-receive his stuff, because that pretty much cops out on the point of the War, namely to settle a dispute. I'd personally recommend leaving a few semi-valuable things behind rather than gifting them away; if he manages to destroy some of your stuff, which will cost you time and money/vis to replace, the Tribunal will likely be much less sympathetic if he tries to declare War again, since he's already gotten to damage you instead of being flat-out denied his War. He has effectively gotten vengeance for his dispute, and more Wars in an effort to physically hurt the other magus would be indicative of several personality issues dangerous for the Order at large.
So, yeah. If you really want to win a War from the defensive side, gift away your most valuable stuff, leave trinkets for him to break, and if he's insistent, repeat maybe once more and laugh as he gets Marched for trying a third time.
This.
Or, if you happen to be a Leadworker fix the AC much quicker than that and then place a waiting ward somewhere in your victim's sanctum ready to go off the moment the WW declaration arrives and the victim enters his own sanctum to prepare...
If the intellego specialist is the one instigating the war, he/she should already know everything in the victim's sanctum/covenant/favourite location and allies. And be ready to strike. (Not necessarily to kill, sometimes simply humiliating the victim is sufficient.)
Intellego = win. Usually. YSMV.
Politics and allies can also greatly affect what might otherwise be a straightforward fight.
Bear in mind, regarding the Intellego specialist (who I agree can have a decent advantage) he can't use some of the most direct effects on his target until the WW starts. Doing so (and most importantly, getting caught doing so) is a breach of the Oath; "I will not scry nor attempt to scry...". Once the WW officially starts, go nuts; and that would be the full moon after the letter was delivered (a month later).
Now, spying without magic is done all the time, and is legal, so again go nuts.
As to what are Wizard's Wars like? My answer would be: Not what Flambeau intended. 
Like pretty much every other operation a magus engages in outside the laboratory, a Wizard's War is a mixture of politics and trying not to get caught doing anything wrong. Whoever's better at that wins. Simple.
Au Contraire, I say it is exactly what Flambeau meant it to be. He was a seasoned veteran (both versiond), and understood that "war" is a complex art. Wizard War has also the side benefit in that it encourages the development of Hermetic Military Science.
As for the Intellego guy, if that's all he's got then he's a goner. Intelligence can mean the difference between victory and defeat, but cannot win the battle alone.
As for fighting a defensive war, well, you already lost.
As I recall in Societates when Flambeau was arguing to put WW in the Oath, he had visions and intentions of formalized and ritualized duels. Glorious and honorable combat methinks.
Now then, that is I think what he intended at the time. Once the few rules were made and he started seeing how the WWs were being conducted i can see him liking the turn for all the reasons that you mentioned. But again, that wasn't what he intended, but perhaps a happy evolution of his work.
As for Intellego, yeah if that's his only club in the bag, he's in for some trouble. But, if combined with other clubs he could be in a good spot, perhaps moreso than the more offensive CrAu dude.
i am sure you are aware of how I feel about the Societates version of Flambeau :mrgreen:
I prefer the version from ToH-Iberia, and working on Faith & Flame, I am grateful we were allowed to introduce the idea that there is contraversy to the truth.
But either way, neither version was a knight of the high middle ages. New Flambeau would have been influenced by Frankish barbarians and Old Flambeau would be influenced by Roman military science.
phone posting results in choppy messages and misposts.
Anyways, there is nothing glorious or honorable about combat. Violence is a desperate necessity and a last resort. Neither version is portrayed as being this reasonable though.For both versions of Flambeau, insisting on lawful Wizards War was to enable him to strike at enemies that sought to hide under the protection of the Code.
No problems here. I tend to go by the published material just as a common frame of reference, I have read some of the posts that I believe you made available, and really enjoyed them, about some alternative history on Flambeau and just finished Faith and Flame and I loved the split between the two covenants inheriting Val Negra's legacy.
I agree that his whole intention for WW was so that his enemies couldn't join the order and hide from him and no doubt also thinking that at some point in the future new enemies would be made.
But I think when he argued for it, he didn't get what he initially envisioned. Why? He had to argue to get it past. That implies concessions were made and things changed from his original intent. But again, I do see him enjoying the developments later on.
The short answer is: "it depends on a huge number of factors".
The magical specializations of the magi in question are just one.
The most crucial factor is "What do you want to get from the war?" Obviously, saving one's skin tends to be a high priority. But keep in mind that during a Wizard's War the Code ceases to regulate the behaviour between the two magi in the War; which means Wizard War can be used for a wide range of activities whose end goal is not the death of the other party. Perhaps you want to simply loot the magical treasury of your opponent. Perhaps you want to extract information from him through magic, without risking charges of "scrying". Perhaps you want to destroy some dangerous knowledge or item in his possession, without risking charges of "deprivation of magical power". Perhaps you just want to prove your superiority (dumb idea, in my mind, but many Tytalus seem to have this Weakness). Perhaps you have promised the local Faerie regent a spouse, and while the regent would only accept a Gifted spouse, agreement of said spouse is a plus but not a really a requisite.
Understanding what you want is crucial in determining which means you should use (and of course, the means at your disposal do dictate to some extent what you can achieve). "Scry and open fire" can sometimes prove a surprisingly effective tactic despite its lack of sophistication - it's particularly effective if you have an arcane connection to your opponent, and he has none to you: you can shoot at him all day long, and he can't shoot back. But there are many other possibilities: direct magic use is just one.
A really important weapon is allies. One of the standard tactics is to "hide" in the sanctum of a powerful friend for the duration of the War; even if the friend is not so powerful, he is protected by the Code, and the risk of collateral damage can seriously hamper your opponent's moves. Or, you can have mutual "treaties" of support with other magi: if any of you receives a declaration of War, the others have an obligation to all simultaneously declar War on the offending party at the next moon - which can be an effective preventive measure. And of course, the smartest choice when you are at war with someone is to disseminate the information to all his enemies - mundane lords, faerie potentates, demons, hedge wizards, and yes, obviously his ill-treated butler or apprentice too. As has been noted, a perfectly mundane dagger in the back (or poison in the soup) can sometimes be more effective than a queen of vis.
Another important weapon is misdirection. The other party will probably attempt to secure at least one arcane connection to you; make sure he gets one - except that it's not to you, but it's to a powerful supernatural creature, or to a decoy you keep under surveillance (particularly useful if your opponent is known to use Tunnels rather than R:Arc spells, in which case you can shoot back). Mark as your sanctum a dangerous locale: a regio of no return, the lair of a deadly beast, or simply the chamber in which the local bishop entertains his lovers. Spread rumors that you are invulnerable (or a powerful curse will avenge your death) unless actions X and Y are taken - with actions X and Y costing effort and reducing the effectiveness of your opponent. Make sure your opponent finds when he really needs it some vis - except it's vis prava (Infernal vis highly susceptible to botching). And again, don't forget the mundane angle: mistaking some poisonous mushrooms for really yummy ones can be deadlier than many dangers of a mystical nature.
One final note: there seems to be little consensus on the forum (and thus perhaps in Hermetic tribunals) where an action with extended effects stands in relation to the "Code limitations are lifted during the War". Suppose you know an ancient non-Hermetic Ritual that, cast on a winter solstice, irrevocably strikes the target dead on the next winter solstice. Is it ok to cast it outside of a Wizard War as long as you make sure there is a Wizard War going on when the ritual kills the target? Is it ok to cast it during a Wizard War, knowing that it will strike once the Wizard War is over? The deadliest shots are often those that strike from furthest away, and not just in space, but in time too.