Thanks, never thought about using it for j.C.
I tried the advance input in another combo instead, the throw -> 214B -> 5B -> air combo, and it works... kinda. If I press 5B too early (as soon as 214B hits), it still doesn't come out. I have to wait for an instant and then press it. Does advance input still works if I keep the button pressed for more than 5 frames?
edit: forgot about this bit:
If I get this right, it means that to make it work you still have to press the button in a 5 frame window before the right moment. If I start pressing the button, say, 8 frames earlier, it won't work. Right?