Highest capabilities-to-bulk small light

I have a DQG Tiny on the way and I’m digging deeper into this topic.
First, as a summary, I am aware of 3 people converting Tiny to triple:

http://forum.fonarevka.ru/showthread.php?t=31935

Each of them adds information not available in others.
The last one contains the following image of the battery tube:
// Doesn’t show as image on the forum, you have to click, sorry…

Doesn’t look like ome could cut a new thread in the middle of a tube; the thread diameter seems just as large as the outer that of the knurling, if not larger.

Any suggestions?

BTW:

it seems that one could shorten the bezel by 1-2 mm…