KB1428 - All awesome! So the big Q is how does it do? What amps and what kcd throw?
I've only fiddled with one XPH35 HI, a stock light, the Manker U21, I reviewed here: https://budgetlightforum.com/t/-/40242. They claim 120 kcd, and I measured 124 kcd. I've done a few HD2010's with basically the same reflector size w/dedomed XM-L2 U2's that do in the 200 kcd range, so from results I've gotten with de-domed XM-L2 U4's I'd expect to get over 200 kcd for sure on the U21, probably close to 250 kcd.
So for the U21, I measured 1.08A at the LED, so if you could run it to 2.5A, dunno, maybe the best you could get is double the kcd? I'm think'n at the top amps for the LED, you would only do about what a de-domed U4 would do at best, but of course, the beam pattern should be different, and probably more lumens with the XPL35 HI, but a lot more power/watts used as well.