This may be stating the obvious, and if so, apologies, but I finally solved a vexing issue. While I've enjoyed the NGX with few problems so far, I have been bugged, so to speak, by one issue - my engine idle was always too high regardless of how I tried to calibrate my CH Pro Throttle and reset my FSUIPC.ini file...I always had N1 speeds of 29-31% and thus had to deal with excessive taxi speed. I finally solved this with a simple solution -- within FSX's Settings menu, I selected Controls and for my throttle, I set its Sensitivity slider all the way to the right and its Null Zone slider all the way to the left. Now I have N1 idle speeds of 21.2% and no excessive taxi speed. No more constant braking to remain under 20 kts taxi speed at the airport. Simple stuff but I was really scratching my head until I finally tried this. Hopefully, it might be of use to someone else.

+1 that's what I did..