I've redesign the mounting system a little bit. Now, rather than using round headed bolts that you have to epoxy into the thruster, you can now use hex headed bolts which slot into the newly designed holes. Because they're hex shaped they will no longer rotate when you're trying to attach the thruster to your frame - even if you didn't epoxy them. It's just better.
I printed a sample piece to make sure it all works, and have updated the STL.