Hi Dave. I'm doing exactly you that is: trying APP for 3 weekes and i love it. I also am trying Siril and it's good too. But regarding background removal and light pollution APP is superior. So i have to decide if going straght to APP (also Mabula is so kind and responsive)...
Then, Dave, i'm asking to you exactly the above question posted by umasscrew39: why don't you give APP directly darks and flats taken with SC? I'm doing this and i think it's a good procedure: APP like darks and flats from SC. I also tried to take single darks and single flats and let APP do master dark and flat: i compare both the final results and i didn't see any big difference. So for me it's more convenient and spare time to take darks and flats with SC and process directly them as master dark and master flats with APP.
Thanks Dave for your fantastic posts from which i'm learning a lot
Ps. Could you please give me your M27 Astrobin link? Because i'm learning the calibrate star color and it's a bit difficult to completly understand the final utility (even if i watched some tutorials)