I did a test awhile back between jb weld and long cure epoxy(shafting epoxy)24hr test time interval.
The jb weld mag popped right off the rotor and the magnet with REAL epoxy busted to pieces trying to remove it.
My opinion is not to rivet them down and use a cheap glue.Moisture will get in overtime and rust will pop whatever screw or rivet.
Do it right and you wont need to encapsulate the rotor in resin either.
Make sure you got things right because once things are set no going back.
Let your rotors develop a little surface rust(excellent primer)for the real epoxy.