Here is a quick run I did with a Slot Machine 21.5.



The spread sheet is available from R1 site.
You can see the RPM plot in blue. Look at how the rpm stops going up as fast when timing goes up. This doesn't happen when running the motor on the analysers without a load. RPM increases in a more linear fashion and you have to look at amp draw. Looking at this data, I would time this motor at 45*. And that directly compares to dyno runs I have made with the MiniPro dyno.