One thing I have noticed is that when I use Amsoil Saber at their prescribed 100:1 mix ratio and run the blower non-stop for a full 15 ounce run I will lose 300-400 RPM.
I'm not convinced this tells us anything about the oil. After all, by changing the fuel:oil ratio you also alter the air:fuel ratio in the engine. By running the oil at 100:1 the fuel:air ratio becomes richer, and rich engines usually run slower than leaner engines.
Running the oil at 100:1 might still actually be bad for the engine, I don't know. I'm just saying this way of testing has too many other variables and doesn't tell us that.
There is probably no way to fully eliminate the influence of the varying air:fuel mixture, but maybe the impact could be reduced by letting the engine warm up for 15 minutes and the tuning the carb to get the maximum RPM possible for each test run. But then again this will only tells us the maximum RPM the engine achieves and nothing about the wear in the engine.