Bob, the "seeing" is everything...well, and good collimation, focus and capture technique
but all the others don't count for anything if the seeing isn't up to it. Capturing good data will give you something to practice with for a long time to come - I'll go back and play with older data if I feel I've improved my processing, as the good nights are few and far between. On a _really_ good night (do we get those?!), with a very stable atmosphere, longer exposures would be fine, but I'm not finding those rushing to come along
There's no silver bullet to finding the sweet spot with your setup, it's just experimentation, but hopefully you've got some new settings to try and see what you think...and that's the important thing...be happy, keep plugging away until you've nailed your capture technique and wait for a good night...you'll be rewarded when one chooses to come along
Yeah the bit depth is a bit of a rabbit hole, but essentially when you stack a large number of frames you claw back the numerical precision you lose by capturing in 8-bit (which we do for speed).