I bought a stock S2+ with an SST20 and want to mod it to a CSLNM1. The problem I keep having is there is a gap between the glass and inner bezel. If I shake the light even gently it is quite apparent. The gap appears to be around 1mm. I have tried using 2 orings between the bezel and the glass but then got some strange artifacting in the beam. I have a few different parts laying around that I can hopefully make it work but not sure what to do.
Are you using a different star for the Oslon emitter? and if so is it thinner than the original?
Try to see if you can screw the pill in further. If so that should fix the problem. However, if the pill was already screwed in the maximum possible, any of the following three fixes should do it:
Replace bezel o-ring with a thicker one; or
Cut a piece of sheet copper into a disk with some tin snips. Place the disk between the star and the pill. This lifts the star up slightly and should fix the problem. Make sure the disk is completely flat before installation and apply thermal compound on both sides of the disk; or
Desolder and remove the star, then use a handfile to file off the top few mm of the threads on the pill. It is those threads hitting the unthreaded area of the head that prevent the pill from screwing in enough to tighten against the lens. If you file off the topmost threads the pill should be able to screw in further, solving the problem.