if your tracking/guiding can handle it, go as long as possible..
I finally got all my guiding issues sorted out for me, and was astounded at the difference between 3~4min unguided subs and 20~30 minute subs.. its rather breath taking really..
Go as long as you can before blooming/guiding problems occur..
and, get as many of them as you can... I generally try to get 2hrs data for an image. seems to be a good place to start...
I've currently got 14hrs 30mins data of M42, 9hrs 30mins to go until I stack them.. Just waiting on clear skies!
