Ive used the JKL setup for most games I play. And the space bar is something i can hit with my thumb to leave my other fingers free to spam bairs.

I use c stick for down and up smash/air. I use keyboard.

I have P for attack, O for specs, I for grab, K for shield, L for Up C, and J for Down C.

I don't, I can't seem to focus on the c-stick and my other controls at the same time.
Also I have like the most different controls from many people here. Keyboard, arrows for movement, Z is A, X is B, C shield and D grab.