Adam, these are good by any standards, and great for a first attempt at Jupiter.
Interesting you've been suffering that slight onion ring effect. I hadn't thought that poor seeing disk distortion might be a cause, but now you mention it maybe that is a factor. Might have to go through one of my "onioned up" avis with Virtual DUb and try and ditch the distorted frames before processing and see if that helps.
Anyway - great pics.