Muto Vim spell guidelines?

Another question from a new SG assisting a new player, need some help with the basics of spell design. This is not a question about house rules or your preferred/hated technique/form combos. Just the RAW (and a bit more, at the end), please...

The player would like to create some spells that can do things like raise the duration or range, of affected spells by 1 magnitude, or change the target to another legal one. These seem to be a "significant" change, which can affect a spell of less than the level + 1 magnitude of the Vim spell. The box notes that "a spell invented according to one of the guidelines below will change another spell in a specific way; it is not possible to invent a single spell which changes another spell however the caster wants. See the example spells for ideas on how specific this should be."

Looking at the example, Wizard's Boost (form), which raises the effect of another spell by 1 magnitude "there are 10 versions of this spell, one for each hermetic form" and "there are other versions of this spell, each of which affects one of range, duration, and target for any form."

If we're reading this correctly, my earstwhile metamagician PC will need 30+ wizard's boost spells if he wants to be able to affect any one of range, duration, and target. and he'll need a lot more than 30 spells, as the change target one will require him to beat an opponent's parma (the others will be used on friendly targets) so he'll need a low-level/high penetration version, a mid-level version, etc.

It seems prohibitive for him to make this versatile metamagician.

He has asked if he can instead use the "totally change" guidelines and (affects a spell of less than half the level+1 magnitude) have his "wizard's boost: range" for example, affect any forms instead of needing a spell for each form, but be limited by 1 magnitude of change. Thoughts?

My thought is that there is no RAW on the matter. The RAW do not make it clear what guideline to use for this effect, if it is possible at all.

My advice is to see the progression of MuVi guidelines as difficulties, and classify such a change as "Total" as the player suggests. However, I don't consider this RAW. It's an interpretation/ruling only.

I note that to affect another magus' spell he would need to Fast-Cast his spell, have a higher penetration than his opponent's, and after all of this the incoming spell must be of a low enough level. And all of that will only affect Hermetic spellcasting. I frankly don't see that as being very likely to be useful. But... enjoy!

I agree with YR7 on the lack of clarity in RAW. My general rule on requiring a spell to be tailored to a Form is that changing a significant part of a spell requires tailoring to a Form while making a relatively minor part does not. I define major and minor parts of spells based on the rules for creating spells. For example, the Technique (Mirror of Opposition), the guideline (Wizard's Boost), or the Range (Wizard's Reach) are all major parts of a spell, needing to be defined when making it. On the other side a casting sigil (Shroud Magic) or casting total (Wizard's Communion) are minor parts, having nothing to do with the spell's creation. Sorcerer's Fork is just strange: none of the Range, Duration, Target, Form, and Technique are changed, but the power does change. My take on Sorcerer's Fork is that it's still supposed to essentially use the same guideline as well, which is why (combined with the previous part) it still doesn't need to be Form-specific. However, I do find that troubling beside Wizard's Boost. Anyway, I find this general rule to fit pretty well with what I've seen in the example spells and the guidelines.

Really, MuVi is quite powerful as it is even though you need so many different versions. Typically, though, magi specialize enough that only a few versions are generally needed. If the player really wants versatility out of MuVi, the player should plan to cast the MuVi spells spontaneously. Let's say the player starts with scores of 10 in Muto and Vim and a Minor Magical Focus in boosting Hermetic spells (most of but not all of MuVi). That's allows for a level 15 MuVi spell to be cast spontaneously. Since you can use R: Touch on your own spells, this is like being able to do any version (R/D/T or Form) of Wizard's Boost on any of your spells of level 15 or lower. Creo eventually becomes a very important Art if want to pursue this really far. Essentially you can spontaneously cast nearly any non-ritual spell with solely Creo, Muto, and Vim. You're unlikely to be better than any specialist in any one area, but you make an excellent generalist.