You should really not fit in survival cards too much in one boss. It seriously breaks the fun. Note that almost all major final bosses have one "survivalish" spellcard in their stock and Extra bosses have a real survival spell.
Yuyuko is the only one with a real survival spellcard, the rest have massive HP and long timer.
yeah, i was going to do the transpearent BG until i realized that i didn't color in the sleeves so they'd be transpearent also.
also, i've noticed that the "spellcard attack!" thing when something uses a spellcard overlaps the cutin that comes in. is there a way to avoid that so it's more like the original?
Actually, the original games have the same style: "Spellcard attack" covers the cutin. =S Here is a good example of Byakuren cutin animation from UFO
http://www.youtube.com/watch?v=h7embor1kB8&hd=1#t=2m04s ( I used her as an example to perfectionize the cutin )
Though ofcourse we can always modify it you know. Like making the "Spellcard attack!" more transparant or make the portrait appear in front of that ( though if you want to make it original it is like: BG -> Portrait -> Enemy -> Spellcard attack! -> Player )