Hey there, just an update. When I put the flongies on dd (had to wait til morning when she was up!), the medium (the smaller pair I made) actually did fit beautifully over the big fluffy nappies. They were a little like grandpa pants (high waist) cos of the extra rise, but the fleece isn't very stretchy so this will help hold them up.

The other pair were HUGE! Will still be fine with elastic tho.

Got some nice stretchy spandex (oh no, 70s flashback) fleece from spotlight tho & am having another go today.

Good luck!!