Tim,
Try changing export Scale-to-fit-Width maximum to be at least the size of your main page 1120px. I changed this from 1000px to 1200px and the scaling issue across your 3 variants looked OK on the index page.
In the version I downloaded, on the mobile variant, MobileGif.gif would not render (checked via Inspect) and it cannot find it. Looked OK in the original URL you posted.
Gary
EDIT: downloaded the gif from your site and all now looks OK.
Bookmarks