[DangerousThing]

Have you started the game? If not, you have more freedom in dealing with this. If the game is already going on, then think about thing, and then talk to all your magic practitioners together.

Perhaps you could use RPM or Realm magic and she would use a set of premade spells without having the ability to improvise until she buys that limitation off. The premade spells might be slightly more efficient than improvised spells if they are old and have been used by a magic using civilization for a long time.

In my campaigns, the advantage of using old spells is exactly that: they may be more efficient than improvised spells. I figure it takes either a magical genius or normal use for at least a century to come up with these optimizations.

Also, magic being occult (meaning secret), many mages wrote down their spells with boobytraps or in such a way that nobody else could use them without knowing the trick to make them useful.