I omitted the driver just to play with it charging the cells to only 3.5v
I have a housing with an isolated battery holder 3 x 10440's and plan to use a LM317 also mounted with a thermally conductive electric isolator pad and grommet, but for the moment I just used a MX-900 with the spring board spring connected to the diode neg and 2 x 16340's put in neg first so the tail switch connects pos to the case. Both cells were charged to 3.5v so it couldn't hurt it.
I checked the part number and it said 7.5v at 100ma even though the original ad said 6v at 80ma and DTR's test was different still, anyway on the bench top I noticed foldback started around 7.5v and 130ma so as long as my cells are 3.6 each or less it works for testing, it seems to like 7.2v at 100ma but I may set it for 90ma, it's enough to see the beam indoors.
I'm not in any hurry and I may use the linear you mentioned, survival lasers blitz linear, although I bet I could find a Chinese board, I'll take a look at the blitz, the spot and color of this 505 is pretty cool, I switched to a 2 element, small artifact up close but nothing far field but a nice small dot.