A big emitter in a small reflector is not the way to build a thrower. Before you go building something custom, have you looked at the Astrolux FT03 with either the sst-40 or the xhp50.2? It’s a single 26650 light, I’m not sure whether you require a dual battery light or not. Both throw pretty far with different sized hot spots and good UI’s stock. Both can be made to throw further by slicing the dome off the emitter.
ASTROLUX FT03 SST40 1900lm 875m NarsilM v1.3
ASTROLUX FT03 XHP50.2 (3V) 4300lm 735m 26650
If you want big lumens in a “thrower”, you might consider the Sofirn SP70. It’s got a 70.2 in a big reflector with a FET driver and 2 x 26650 batteries. It’s also got a nice ramping interface stock.