Or if you limit penetration for items to something like Casting Total or (Penetration Ability)*5 (Although items still are interesting and powerfull)
Much as I hate having another skill for Verditius to have to buy up, that's really solid, Fixer. I would suggest going one step further, and instead of Penetration*5, use the penetration rules, the part that gives multiples. Having to have various degrees of Arcane Connections makes that "Wand of You Will Die!" much harder to make and gives you a story, as well as stopping cold the mass manufacture of charged items, while keeping Effect Expire a useful part of the game.
The real ultimate power Mystery combo is expressly forbidden in the rules because it would be just too powerful: the combo of Verditius with Craft Magic.
All of a sudden, with Enchanted Casting Tools, the Wand of Kill the Giant F***ing Dragon Like He Was a Flea becomes something you can make on a lazy Sunday, or pop out by the dozen in a summer when you're short on cash.
Might make for a good opponent (someone overcomes the in game prohibition by "Hermetic Breakthrough" and is Up To Something....)
Good luck stoping him, though.
He's got 100 buddies all of whom have fire wands with 70 penetration.
No, it's not expressly forbidden. Somewhat the opposite, it is suggested that Verditius magi would like to acquire Craft Magic, but the owners of it aren't so likely to share it. You lose it if you go through Verditius Initiation already in possession of it. But that doesn't stop you from getting it afterward.
Chris
Or just go with charged items and have 20 charges of a level 94 effect. the two seasons and save the 18 pawns of vis. Well structured covenants can be really really scary if they have a season or two to prepare. This probably goes a long way to prevent rule of force by wizards war, if you piss people off enough they will get you even if they are not any where close to half as powerful as you are.
Lab Total 99 for a level 94 effect yields a single charge, not 20. You must have missed the errata.
unless you have a lab text
I must have as well, linkie please?
Because as far as I can see, Lab total 99, for effect level 94 gives a single charge (or 2, depending, but who's counting?) for the first season.
But the next (and successive) season(s), I have the lab text and gain silly amounts of charges.
And I must be blind, since I can't find anything to contradict this in the errata 
True, the first season you'd have 1 charge, the next 20. I thought he was going for effect expiry. 
And you seem to have missed the note about two seasons. For the second season you will have a lab text after all.
Also 20 rods of smitting in the hands of grogs are quite possibly more useful than the more uses an item with expiry could give.
I made amends 12 hours before your reply. You must admit your sentence was not easy to read and is still off by 1 charge and a few pawns of vis, enough to confuse anyone.
The Vis was exact. A level 90 item only takes 9 pawns of vis, so 9 for the opened item, and 9 for the enchantment.
And you could always not do triple overtime and cut a few points off your labtotal as long as it gets over the effect. It does not make sense to go crazy to boost your lab total for a charged item unless you expect your lab total to raise, but pushing it a bit can be worth while.
How did 94 become 90? Are you mistakenly rounding down or is there another reason?
Because 90 is all you can do with a lab total of 99 in two seasons. You have a more powerful item using a charged item. You have to compare the effects of the same lab totals right?
You get 4 levels more effect and probably more on top of that when you figure out uses per day that you don't need to worry about with a charged item.
Yeah, 12 uses per day would sound fine for an invested item. An extra 8 Penetration but 1 use per day would be tempting the SG.