Tap Jump: off
R-stick: Smash
B: Attack
Y: Special
X: Grab
L: Shield
Zr: Jump
The vast majority of things I need to do are covered by the above. My index fingers naturally rest on L and Zr, and I see that changing jump to a shoulder button isn't all that unpopular. Moving A+B to B+Y emulates the N64/GC controller layouts. X swapped to Grab because there's no better place to put it. It's a slightly roundabout way of doing it, but pressing UP+B+Zr while holding shield gives me Up-B OOS, which isn't possible simply using defaults+tj off.
Zl: Grab
R: Attack
D-pad: Taunts
A: Shield
Zl is an alternate Grab so I can do instant throws and boost grabbing (x + cstick doesnt really work). Neither grab position is ideal, but having two sub-optimal positions is better than just one. R for attack allows me to DACUS by holding the L-stick sideways (run), smashing down on the R-stick (dash attack), and rolling the L-stick up while pressing R (Up-Smash). It's definitely much harder with the defaults, if not impossible. A can be anything but taunt, and is now shield, because the only time i ever touch this button is when mashing out of grabs. I have no love for that button.