I always try to use my numeric pad in for every emulator. Only go to other keys if the numpad is not supported. I use something like this:
A-------A+B-------C
B-------B+D-------D
B+C---unused---B+D
Which are:
7---8---9
4---5---6
1---2---3
Pad buttons are up=w, down=s, back=a, fow=d. That's how I use it.