Okay, I'm glad I asked. The FGC needs more love, and less people acting like assholes to each other. Namco really needs a better tutorial system. I spent so many hours in Tekken 3 figuring some of this crap out, and now the games so far advanced beyond what I learned.
So here's buffering. I'll use the buttons as identified on the controller. I'm pretty sure this is right. So;
Square = 1
Triangle = 2
x = 3
O= 4
So if I'm trying to do a move where it asked me to go from X&O (3&4) to hitting O&Square (1&3), I'll hit x and 0 with my thumb. I'll then leave my thumb pad on the o and simply slide my thumb up to square. Make sense?
I didn't release all the buttons and repress them. I kept O pressed down and then hit square. The game registers that as two separate inputs for O.
The chain throws are still really hard to land, and a lot of them you still have to do the old fashioned way (separate inputs). But if you combine button buffering with shoulder button mapping, it makes it achievable.