How to tune ThermoQuad secondaries?

OK, thanks a bunch for the help.

1) I can just remove the top part of the carb with it on the engine, right?

2)The secondary jets have the number 5125 on them. According to the Vaanth ThermoQuad guide that's a .125 jet.

3)I'll check the air door travel; exactly how much distance should there be though from the carb body to the top of the air door when it's fully open?

4)The float level should be fine, I checked it multiple times when rebuilding the carb. I'll check it again though when I go to clean the secondary circuits.

Something interesting about tuning at this altitude, I brought my Traxxas T-Maxx (nitro-powered RC truck) here from central PA and tried to tune it to this air. Everything I read said that it should be leaned out, but whenever I'd run it it would act like it was running super lean (even with the screws set the same as back in PA). Turns out it was lean, and when I finally tried richening the mixture it started working better. Unfortunately the engine was toast by then so it didn't matter but it was interesting. BTW those run on a 20% nitromethane/methanol/oil 2-cycle mix. This might relate to my current problem.