Just gonna throw a notation in here. Me and my crew just had a session today using the rules that you can use evocation blocks as a "reflexive" action in response to an attack and i have to say it didnt seem at all OP(over powered) to me(and we had two magic on magic duels) It just made the magic user harder to hurt at first but then suddenly like two rounds later when they dont have any stress left to spend on spells they didnt seem so high and mighty anymore.My personal oppinion on it, is its not OP or anything because it causes the mage to be harder to hurt earlier on but they have to sacrifice ALOT of their magic stamina for it. Just in case that helps in anyway. If not sorry for disturbing you guys.
Cool. Having a player say, 'I'm getting ready to launch my shield as soon as I see anything even vaguely nasty' pretty much always wins initiative in my game anyway
In my game, that might win a false alarm that I would make them still pay mental stress for putting up a shield.