As Eric pointed out, AAVSO’s Gary Walker and Arne Henden have been the pioneers with CMOS precision photometry, at least with production cameras (the FLI Kepler and ZWO cameras), to include big-scope professionals. If you could reach out to AAVSO, maybe join and access their discussion lists, you may find a path to success. Again I am no expert at all, Eric and DIck are far more knowledgeable. I just know that no one has asked me to alter the way ACP Expert acquires sky or panel flats until the last couple of weeks. This makes me think that maybe some article or forum discussion has caused people to look in this direction.

What do I know? But if you aren’t using both bias and dark frames to calibrate, you’re open to variations in exposure time.