FWIW, Taking flats for a rotate position is really to take care of dust donuts on a filter only. Also, for now you could take flats at given angles and store them in a folder name like Flats_90, Flats_120. Flats are not usually needed every night unless you are doing science. I do my flats on cloudy nights, of course I a have a light panel so that helps. I would try taking flats at 0 and then apply them to images at another angle, you might be surprised. If dust is on the filter, that is easy to fix with cleaning when on site.