As a photographer myself I really don’t recommend the Cree XM or XP class emitters for this. The big MT-G2 makes fabulous light and will have a fat hot spot much more suited to light painting. The C8 will have a small hot spot that will make light painting iffy at best.
Nichia 219B puts out a nice tint, but is usually on the weak side unless you use a small triple, which would then have a wide spot and the high CRI abilities.
Pairing up internal USB charging AND throw with a good color profile is somewhat tough, especially trying to keep it small. How do I know this? It’s because I started with flashlights as a supplemental lighting source to shoot macro images at venue’s, like ring shots at a wedding for example. I now have 160+ flashlights and still can’t say there’s one particular light that works best for photography. The closest I have probably is one I built myself.
A Convoy L6, converted to MT-G2, is a very nice light to use in a photographic sense, but it’s not small. I have a BTU Shocker with 3 of the 9V MT-G2 emitters I like to use, it makes a whopping 10,000 lumens if desired, with 7 levels to choose from, but again, it’s a large heavy bulky light.
Good luck! And welcome to the insanity…
Edit: RMM (Richard) has shown a dual MT-G2 that he is selling cheap, $105 I think for a $150 flashlight, that one is pretty small, makes a whopping about of light (in the 5000 lumens range) and would be really ideal for your set-up, not sure if it has built in charging or not. (I’ll go find his post and link to it here… brb)
Edit II: It’s the Niwalker Nova, pretty unique light, only has he one, better give it a look and act fast if it’s for you…
Edit III: Richard also is selling a 2x18650 MT-G2 light that he put together himself, should be a good choice but might be on the warm side at 4000K, you can work with it though and it’s $55, his driver as well. You should really talk to Richard… he knows a good bit about photography too. 