I like where they’re going with this… 
SKV89, Richard (RMM) built an TR-J20 with XHP-50.2’s I believe, also added a slave driver. It made 39,000 lumens and got too hot to hold within seconds. I made a heat sink to tie in the excellent finnage and he said it would then run til the cells died, it got hot, yes, but was dispersing it faster than than the cells could hold up. I had also made him an extension that was finned to match, for a 4th cell in that big light. 4 32650’s in series. 
My own is still running 3 32650’s and has 4 of the 9V MTG2 emitters. It’s making a lot less than Richards, but a lot more than 10,000 lumens. Same heat sink. (made the same of course) I also added a 1/4” thick spacer up top to accommodate the reflectors.
Edit: Rested and at 4V it makes 11,612 lumens. Edit II: 12,976 with the cells fresh charged and at start. Mind you, the cells and emitters are going on 3 years old.
