Try the custom AI to help you find products that Reddit loves.
I've looked at doing this exact mod a couple of times in the year+ I've had my JMJM.
Currently, I'm using this roller TOM bridge off Amazon. Even though I haven't added any shims to the inner saddles to bring it closer to the 9.5" neck radius, it's working much better than the stock bridge. And best part, zero modifications to the guitar. The thimbles for this bridge actually just dropped into the stock thimbles, although I did add a few wraps of teflon tape to snug them up a bit. (I already had an extra ground wire going to my vibrato so I wasn't worried about losing the bridge ground). I'm extremely happy with this bridge so far, will likely get better once I get it to the 9.5" radius.
But, at some point I plan to do this mod as well so I can decide which one of these "zero mod" mods I prefer. Interesting to hear about the Graphtech saddles though, I'm quite the fan of their TusqXL nuts, but may stay away from the saddles judging from your experience.
No, I don't think that will work, the saddles mount completely differently. And if it would, it would still end up being a 12" radius bridge.
And for reference, this is the bridge I got: https://www.amazon.com/gp/product/B01JLHA55C
Basically a generic Wilkinson locking roller bridge.