I used a two part epoxy resin. Extremely permanent. I'm all in where found parts are concerned although I appreciate that many see them as an investment and are reluctant and fully respect that although I also think some unaltered parts look silly (Like a replica saber with an MPP plate or the Nemrod holster is another good example). I think in this case however that a semi permanent solution could work quite well before your ultimate butchery for the EE3 although I'd wager once you end up with a nice saber you'll want either another MPP OR replica MPP for your EE3!
I'd consider superglue which, to be honest, is anything but and comes off quite easily with picking. Double side tape might also work. Why not try some different ideas on another piece of chromium plated metal to see what works?