From my race testing, I went with the 6amp setup on the latest Maclan V2 with both the stock rotor and also with the upgraded higher torque one.

I noticed in the 2wd 17.5 buggy spec class fade that would happen probably about 4 minutes into the 6 minute race. Temps also were higher than I liked even with a fan. Changing gearing to compensate affected this very little.

Track is astro about 100 x 80 sqft.

After seeing the settings mentioned on the maclan, I went down to 42 degrees which if I recall was about 3 - 3.5amps (I have to look at my notes again) for draw on my analyzer.

Out on the track the motor was a screamer now all through the run and I noticed a bit more low end punch too that was missing.

Guys who cars have that "fast" look to them when we would do some drag sessions down the straight, my vehicle was right there with them.

Considering my vehicle is a heavier conversion too, the Tekno EB210, it put a big smile on my face.

I would say that method comparing your RPM, etc gains versus amp draw might be the better way to go.

I use the same method myself. Small increases in can timing until you get that huge jump in amp draw for no more rpm.

Just like everyone here, i used to do the 6A draw setup, and i couldnt get temps down. when i finally started doing my own spreadsheet, and learing where the motors sweet spot was.. i could get a motor in the 3.5-4A draw area, then i could gear effectively for that. the whole set it at 50 and go.. just doesnt seem right. i mean.. in Texas.. we are racing at 100* ambient temp.. to only gain 60* temp in a motor is just not going to happen running at 50* timing.. if i had the means to do a video, and show what i do to get the correct setup.. i think people would understand it. everyone i have shown this to.. end up loving the setup, and then.. a few of them have started getting their own analyzers to do their motors..

This is the reason I am testing different motors, everyone has their own tuning methods. I have my personal methods that work well for me, but I wanted to give each a try and see what works best with the dyno and the actual performance on the track.

I'm still awaiting on one more motor to get approved by ROAR (ETA ? TBD) before I start my track testing. It would only be fair to test them all on the same track, same day.

Actually there is more to it than max efficiency, must consider the max RPM, MAX torque, MAX Output (power), least current draw. Because your right to a point that max efficiency without the other numbers is defeating the tuning process. So I will be doing several methods and trying to find the sweet spot for "each" motor. One size does not fit all.

I believe my results are an anomaly. I will know more when I tune 3 of my slower motors to see if their is any "real" performance improvement.
Also the motor I did try it on first was the best pony in my stable. It is crazy fast and strong on the track,