nabla: I've played a game and used the checkers from an other board so we've had different colour for the 'racers'. I definately would suggest that well.

And downloadable MAT-files for BG!

Marfitalu: Yes, Shogi / Loop Chess are good comparison points. But for me, about anything distinguishable would do it.

nabla: I agree. It can be very confusing and if you don't pay very careful attention, it is quite possible to make a critical error. You could always look at move notation and judge from that, but that does take longer and you are more prone to making a mistake.