Thanks so much for doing all this research. I too use a Runn on my NT incline trainer. Your solutions will make my trainer even more useful. I’ve been measuring the angle and adjusting manually for each workout while using Runn to report the speed more accurately.
The real question we should asking is why NT can build a $1500 device that is consistent in speed and angle. Mine has so so many problems I can’t begin to list them all here.