I use Dave Ek's digital setting circles with my 10" starsplitter dobson. To use skysafari with my scope most comfortably I have attached my phone side by side to my ocular. To my surprise scope movements moved skysafari's skyview, but DSC was not powered. Ok, this was from compass mode. It looked quite promising to skip my encoders and use phone's sensors instead.
And this is my feature suggestion : add a new type of pushto scope to your list and use phone's sensors to get azimuth and height.
We have looked into this many times. The phone's sensors are just not accurate enough to do this reliably. The digital compass only has an accuracy of 10º-15º.
Sadly you are right. I tried to get reproducible azimuth measurements on my floor with rectangular patterns on it, and tthe angles did vary by 10degrees. Thus I can't sent my DSC into retirement.
Thanks for considering my suggestion,
Michael
PS: sorry for typos, but Google tries to fix my typing in this window using German language.