Tom,
For the Nuwai TM-301-5, I used strap wrenches to break the threadlock to open.
Once inside, I measured the voltage across the Lux V emitter, it was nearly 5 Volts. I knew I couldn't use the stock board driver.
The "pill" is simply a Lux V star, an emitter board, and an aluminum spacer in between.
Since the Cree board is thinner... plus a Cree normally needs "lifted" to go into the reflector far enough, I decided to double-stack the Cree star on an empty star I had laying around. I used thermal epoxy to bond them.
Also, I decided to wipe all the components off the driver board
and simply wire directly to exposed solder pads that connect directly to the battery terminals on the other side. This means I would need to use a 3.6V source and direct drive the emitter. Before I did all this destruction, I wired the emitter to the battery and found it uses a safe 850 mA.
The only other modification I needed to do was open the hole in the reflector and allow the emitter to go up inside better. Also, some material needed to come off the back. I filed off the boss/step of material off the back of the reflector, and the result was a hole big enough for the emitter, and clearance for re-assembling everything without the reflector hitting the Cree board.
Put it back together with 1 RCR-123a and 1 dummy 123a. Turned it on, left it on, started comparing against my other lights.