Hi Greg, it’s a nice high resolution picture indeed, although as others have said flats will help bring out the asymmetrical shell around the lmc. You have definitely captured it, but because of the uncorrected vignetting I’m sure you’re seeing a combination of the halo and the illumination drop off. Here’s a similarly deep image that has been calibrated and is inverted to show off the cirrus. Taken in remote WA with no light pollution whatsoever, and you can see the halo isn’t circular.
https://www.astrobin.com/309256/
Cheers,
Andrew.