Yeah, to date I haven't found any compatible boots for these gear links, not that it doesn't exist. I also tried to find a neoprene sleeve for a pen/cil thinking that might work but nothing found.
I have found facilities, mostly in china, that will make bellows to order, but don't need 1,000 of them
Even the one's I ordered 3 weeks ago, had to be factory ordered, and I'm still awaiting them from the U.K.
I went with the ultra bond superglue as part of its marketing was a video cutting a bellow and bonding back together. When I glued these up, I didn't do just the valleys but peak to peak..
I've never heard of shoe goo, but is it flexible? That's why I experimented with Plasti Dip. Yes, it does peel off but might at least add some protection. Otherwise, mostly useless stuff.
Probably a futile effort, but worth the engineering experiment effort to me.