Greetings you guys down south!
The movie mode might be the way to go. Just let the planet drift thru the FOV and then later go back on the computer and go frame by frame and pick out the clearest frames for stacking.
The only major down side is most cameras compress video frames to save space so you end up with more artifact and grain.
So taking a bunch of stills and weeding out the bad frames might be better quality wise.
Astrovideo is great for webcam work.