I figured that most of the games I want to play only require 2 buttons, so I was thinking to swap button 1 and button 2 colours. I'm not yet sure what would look the best:
A) Player 1: red joystick + red buttons 1,2 + blue buttons 3,4,5,6
Player 2: blue joystick + blue buttons 1,2 + red buttons 3,4,5,6
or
B) Player 1: red joystick + blue buttons 1,2 + red buttons 3,4,5,6
Player 2: blue joystick + red buttons 1,2 + blue buttons 3,4,5,6
The picture shows colour scheme B, but while fiddling with the colours I might take scheme A, it gives buttons 3-6 a more secondary feel (which is what I'm aiming for).