You almost certainly need a new cover as they are shaped specifically for each wheel. If you cut the old cover, they remaining pieces likely would sit too far apart from the rim surface to tape down.

It depends. How good are you at arts and crafts vs how much disposable income you have?

Me? I'd sell the Boyd wheel with the cover and buy a new cover that fits the Flo 90.

I've done it with sketchy results. I cut one down and enlarged the center hole to accommodate a different hub. I then learned that spoke count matters and I had to cut all new mounting holes. I consider myself pretty handy but it never fit right after that and I ended up buying a new one anyway.

Save yourself the hassle and buy a new one.

So, I scribed the Aerojacket, and cut it down. I think it worked OK. It isn't a perfectly flat disc surface, but seems fine. If I can figure out how to post a picture, I will.

Make a video to show the wobble.

https://photos.app.goo.gl/9QHjkxvAiV7RJAiJ6

It's a bit annoying to open, but the video is there. Click "slideshow" if you want to open it.
There is a bit of a bump over the inflator cut out, but that is as good as it is going to get.