Are you planning on getting sound? The thing about using the Grand Master is it's probably one of the thinnest lightsaber designs, along with the Empress. I had sound on both but dueled with them and the battery case (with sound) is now jammed to a higher part of the hilt. It could have changed since the Grand Master came out 2 years ago. If no sound, get Grand Master. If you want sound or a more manageable saber, why not get 2 Saviors. It's crazy long and skinny but zero problem with batteries, electronics, etc.
The quick release coupler is cool. It wobbles a little bit and the sabers will spin, but I hear it can take some punishment. If you decide to get the Saviors, they're like crazy long so a smaller size coupler would work. Also, the Grand Master doesn't quite give me enough room to spin thanks to it's non-removable emitter, which sadly won't hold a blade plug. It has awesome aesthetics, I think, but the real winner is the Savior. Plus you can get a Manticore emitter. Have a spin able Savior with Manticore windows.
Post pics. Stay sharp in the Force.
I have to say... I don't get why you keep pushing the Savior when Smeeg699 said he knew which one he wanted... and it's an AGM.
Granted, you pointed at some negative points on the AGM but still ^^'