I've finally gotten around to processing M42 again with the extra data I gathered before Christmas. This brings the total integration to circa 5 hours. Doubling from the original 2.5 hours has made a big difference to the SNR as well as the fainter dust around the nebula.
Esprit 80
533MC
EQ6R
UV/IR Cut
Lights ~150 * 120s
~100 * 10-15s for the core
Darks
Flats
Dark flats
Bias