Not an expert here Stephen, but from memory.... its been a while .... flats would help with dust bunnies etc. I think it is BIAS shots you need to take maybe. I think there are flat/bias and dark/bias aswell......I have been looking for my notes and bookmarks on this in the last 10 mins but cant find..........
Bias, I believe, is when you you take a shot at the fastest shutter speed with a white background.....
pleas correct me if I'm wrong guys
bartman