Many thanks Mick, I didn't realize (forgot) it was marketed by Chiselspeed and I just found your chart and some more information on their website and also MB have some additional info BUT it seems a bit confusing to say the least

Chiselspeed say it retards and MB says it advances

I reckin I'll just have a play with it and see what it does, at least it's easy to adjust timings with the external pickup
