I don't think you can say which is better... higher compression or higher rebound... It all depends on the situation. From what I've read and understand, full scale off-road like motocross or snow cross typically run an FV that has lower high speed (less pack), and a lower rebound for better launching over jumps. But then again, you might find riders running a little higher rebound to feel a little more planted. It all comes down to personal preference. I'd say experiment with both directions of piston and see what you think works better. By changing viscosity, you can keep either the compression or the rebound the same, and increase/decrease the other end.

I wouldn't yet say you wasted your money. I will say that in LOW VELOCITY (pitch and roll of car), the taper will have little to no effect. I have not yet tested impact (jumps), and there could be a difference in the pack qualities. That's the main thing I really need to test, I think people want/need to know that. (by the way, I've also spent my own money on all these pistons I've tested myself.... all for the sake of testing

Me too... I did this for a few years as a kid, had a couple RC10's. Just got back into it for the engineering marvel, and I'm trying to understand it. That's why I built the dyno. Might as well share the knowledge instead of keeping it to myself. Thanks.