Looks like you have the technique down pat now it is just a matter of playing around with capture settings to get the most out of what you have.
Mike Salway (iceman) wrote a great article a few years back which still has a lot of relevant information nowdays - you can read that article
here on this website.
Been a while since I imaged with the webcam but the basic principle is to show your histogram and you want to have your exposure maxing out up at around the 90% mark to give you the best data. There are several ways you can do this and how you do it depends on the seeing conditions.
If seeing conditions are excellent you don't need too many frames, and you want good quality frames with minimal compression, so you target a lower 5-10fps. If seeing conditions are poor, you don't worry so much about image degradation due to compression and you can target more frames, say 10-25fps.
You will need to balance shutter speed and gain to get the histogram approx 90% exposed. With good seing you can use less gain and a slower shutter speed, with poor seeing you will likely use a higher gain and a faster shutter speed to try to get those rarer good frames through the atmosphere.
Best of luck!