I use d=up, x=down, z=left, c=right, f=up-right, s=up-left, search= down left and down right which basically makes it equal another down button. Reasons for my controls. It is easy to hit x+ z or c to hit down diagonals and feels more natural. I assign buttons to search cause it is easy to hit that button by mistake instead of x and if no buttons are assign it will take you to a search window every time, now instead it is basically another down button. I've experimented with many control sets and this works best for me, especially in game where hitting diagonals is a must. It takes a little getting used but I believe it is the most efficient scheme.
P.S. I stay away from the top row of buttons cause my I dont like my thumbs touching the bottom of the screen when I try to hit keys.
