Interesting concept to make them less effective, though, for those hating on them even in their official nerf form of use.
This where you have to cast them on your turn, pre-attack, akin to Landing where one dies from a rock slide before it’s their turn to Instantly cast the spell, due to traditional casting rules.
Many allow “Defensive”/Healing casting any time during a round, as a House Rule, where one simply docks 10% from their next Init phase/round/turn.
Much success if you do use RRs.
Let us know how it plays.