Actually just finished, buttoned it up. Will do some more testing, and lube up the threads better, than I gotta do some underwater testing.
Stock, on 2 K.P. 4000 protected full charge, Hi: 2.48A tail, 2,305 lumens @30 secs, Lo: 724 lumens
Modded with added R120 resistor (stock: 2 R160's), upgrade LED wires to 22 AWG (stock looked like 24 AWG), 22AWG bypass on driver spring, cleaned LED domes (little dirty):
on same cells full charge, Hi: 4.84A, 3393 lumens @30 secs, Lo: 1.44A tail, 1095 lumens
Throw looks good outdoors, but didn't measure it yet. Overall, I'm pretty impressed. It holds output really well in the 1st 30 secs. Was thinking they probably are using XM-L2 T6's, but could very well be the claimed U2's based on these #'s. The LED's are 2P/2S, and think they get 2.0 to 2.3A each, and result in about 850 lumens per LED, which is pretty efficient. Also my bent PVC light box might measure these multi LED flooders high - not sure.
The guys this flashlight is for do diving in freshwater, but pretty deep, maybe up to 100 feet. Wondering if the cool white tints are ok - thinking the neutrals would be better in unclear water, but really dunno...
Darn cheap mod so far, if I keep the stock LED's and MCPCB. Doing copper DTP's would be a PIA - 16 mm's would probably have to be cut down, and the positioning would be a pain to get right.
Update: throw measured out at 25 kcd (316 meters). Was hoping for better but the reflectors are pretty small and I'm sure the thick glass cuts down on it.