Aero-> Tornado
Fire-> Fira
Fira-> Firaga
Blizzard -> Blizzara
Blizzara -> Blizzaga
Thunder -> Thundara
Thundara -> Thundaga
Double -> Triple
Aero-> Tornado
Cure -> Cura
Cura -> Curaga
Blind-> Pain
Bio-> Pain
Silence-> Pain
Slow-> Auto-Haste/+million% spd (for status protection. Why would you be casting slow anyways, it never hits anything >:[)
Float-> Quake (as far as elemental protection goes; you won't really need the actual float spell if you have 100% absorption of earth damage anyways)
Apocalypse-> You can't draw it until the last battle and you can't junction it unless you use a gameshark or whatever.

and that's 17 8)