Alright I use:

Column 0 - R
Column 1 - T
Column 2 - Y
Column 3 - U
Orange Line Left - 4
Orange Line Right - 5
Blue Line Left - 7
Blue Line Right - 8
Wide Notes - Space
Wide Notes Alt. - V
Steer Left - E
Steer Right - I
Boost - W
Dedicated Hyper - O

This focuses on making it easier to do finger gymnastics to hit the stuff in this game.