My strategy was use a deck suited to Sleights. So i could use most of the use full ones at least once, if you haven't been fighting with Sleights much nows the time to start. Most Attack Sleights are Useless against the spectre form except for Blitz which has fantastic tracking against aerial enemies. Firaga Burst, Raging Storm and ranged magic work well against the Spectre Form.
As for the Angelic Form, fuçk away at him with everything you've got, watch his moves they're telegraphed well and dodgeable, except Omni Laser which is a bitch and Gale of Severance but the last ones alright. Sonic Blade, Ars Arcannum, Firaga Burst, Raging Storm, Holy, Donald & Goofy Sleights, Blitz, Quake, Lethal Frame, use everything!
I'm sure you keep a couple "0"s anyway but my habit is keeping them to the left of the charge meter for quick access with the up directional button. Short cutting Cure to the down directional button for instant regeneration, a Vexen Card just incase. (the fights are consecutive but you can use it once in each.) Thats probably all I can offer. Just one last thing keep a mega elixir handy to reset your stats after loads of Sleights.