Setting timing based off an unloaded amp draw is (in my opinion) a stupid way to do it. The ultimate goal is to have a car capable of the fastest lap time without getting the motor too hot.

There are so many other variables that dictate the actual best motor timing and gearing. You would be much better off putting everything back to where it was and run the car to get a baseline lap time for that day. Then make a small change to gearing or timing, run the car again and see if you went faster or slower. Although, if you crash a bunch (more than one or twice per race), these small adjustments are not going to mean anything more than your car is going a tiny bit faster when you crash.

Can you run an entire race without crashing?

Also the 6 amp vs. 3 amp thing is because newer generation motors are more efficient, so they will draw less current at their optimal setting.

It doesn't matter what anyone else is doing. They don't have your motor or car, and they don't drive like you. Make small adjustments and see how the car performance changes for you.

Finally, this really should be posted in the Radio & Electronics section, not Electric Off-Road.