so the best we found was at 20.45 deg BTDC. A peak of 78, and over 70 from 7500-8500rpm. very strong. measuring along the circumference of the rotor, its 22.5mm from the factory mark. did some math and figured out every 1.1mm is 1 degree .
going back to 2.2mm / 16.2 deg / 17.8mm you're down about 6hp over a 1000rpm range.
at 1.5mm / 13.3 deg / 14.6mm youre way off the mark. down over 10.
it will barely run when its set at TDC
didn't advance any more than 20.45 deg. thought we had gained enough. we likely could have though.
This is running c12, checking plugs, fuel flow, egts. all that good stuff. use at your own risk. Mine's staying at 20.45 though.