My right hand homerow is on top because I have bigger hands and imo it's easier to slide downward than upward for inputs accross rows
B / C stick cluster (right thumb)
my cstick is cycled because with the defaul layout, I thought c-left and c-right were too far apart. With my layout, cleft and cright are directly next to each other. (Note for me C left is the most awkward to press fwiw) C-Up there is easy enough for up airs and upsmashes so it's fine.
B (and X, and R) are where they are because it unlocks the same muscle memory as when I play gcc in claw (left index jump, right middle shield, right thumb b/c-stcick). This made switching a little easier and gives me acces to certain muscle memories like side b shorten a little easier. I lose out on certain shine techniques: such as choosing options out of shield requires some setup for aerial vs shine oos.
A: I had to put it somewhere so I put it on the left pinky.
L: This lets me wavedash out of shield by sliding my index finger down from X → L.
I nearly never press mid-shield or Y. I do sometimes use my right ring finger to use light shield.