Gah, my great big post got deleted! OK can't be bothered typing all that out again, but I've been putting in a lot of lab time with Cervantes' wall game and this is what I've found:
Almost any wallsplat, slightly delayed 44[A+B]
If your opponent doesn't stay down after the wallsplat, he will suffer UNSPEAKABLE CONSEQUENCES - 80-100% from the simplest of wall combos depending on angle/followup.
You need to slightly delay the 44[A+B] or sometimes it can whiff. I do it just a little bit after their feet touch the floor.
I like to use it after simple things that are consistent like 3B w!, 4K,K w!. However, testing suggests that you can use it after any wallsplat, any angle, any distance, except:
(Wall on right) 3B w!, 66B attack throw w! - works but timing changes to hit consistently depending on the character
(Wall on right) 3B w!, B2 - too inconsistent
(Wall on left) 3B w!, bA - too inconsistent
Anything else seems to be fair game. This, combined with other things after a wallsplat like 2A+B, 1 B+K ~ G cancel and dread charge turn Cerv's wall game into a horrible mindgame for the other guy. Its brilliant.
Can other people test as well to make sure its all good?