Finished my light mount design:
Wired these up to the battery via this LM2596hv buck (you win @b264 
) and they lit up first go!
Was pretty impressed, not only with the light output, but the fact they still work. When I had them strapped to the front hanger with their included bike rubber band mount, one popped off mid ride. It was dangling from its wires. Before I had a chance to secure it, the wire actually ripped off, the light hit the ground, bounced, and landed back on the deck next to my foot. I snagged it and put it in my pocket - all at ~20mph 
I cracked the light open to check damage, assuming I’d have to order another from Ali. Clean rip right at the board. I was able to disassemble the whole thing, suck the solder off, and reattach the + and - wires to their pads. Reassembled, coated the wire exit in silicone, loctited shut, and installed. Good as new.
While I was at it, I decided I’d prefer to never get a flat tire again. Went all out - tire liner & slime.
21" length of Mr. Tuffy Bicycle tape covers the interior wall of an 8" knobby tire. I used the 20x1.95-2.5 size for the width, mainly. Fit well. Plenty left over.
Slimed all 4 tires. Used most of an 8oz bottle - although this was probably way too much.