Gt. Saiyaman is weird.

On the one hand, using Justice Punch and cancelling in the middle of certain things (almost instant startup) can make his combos pretty extensive. On the other hand, I can't break 1000 damage even with a stylish 23-hit combo consisting of aforementioned JP Roman Cancels.

PPPKK-, <PPP<E-, heavyslam, >KKK<E-, KKKK-, >PPPPP<E

Not sure if this is general knowledge but, and don't hold me accountable for this, but on top of this, I think Justice Punch can be FalseRomanCancelled too if you hit the guard button at the right time (like, the instant it's possible to cancel it).
This might just be a glitch, but there would be times where midchain, I'd cancel the JPcharge almost immediately and the move would still be buffered and I'd still get the cancel chain, but I wouldn't lost the Ki I'd normally do for activating a deathmove. Not even the little "vrrrriiiing" sound you hear when you start up a DM or capsule. Just a completely silent and free cancel.

I don't have any video equipment, so I'll show footage of it the next time I see Aqua.
Training mode is an interesting, interesting place.