I also defeated the Giant Cactuar, and in the process learned that mini-cactuars offer 20 AP Each. Squall can knock one dead in one hit, so this ended up getting me ~ 200 AP in about 5 minutes.
Earlier in the afternoon, I also killed Odin, so I will be able to obtain Gilgamesh when I head to Lunatic Pandora and take on Seifer.
At my best, I boosted Shiva to 175, Leviathan to 235, Pandemona to 210. I got Ifrit to 160. My boosting skills are at an all time high.
Diablos is now level 35, so any characters on whom his attacks work can be dead in 3 rounds max.
And no, this isn't all euphemism, nor some strange code.