This is a very nice development 
i thought early on that the new FET+7135 driver would be a perfect fit for this, but i didn’t want to complicate the process and then it was still untested.
I think the running times would prove to be advantageous and what other light is this bright, edc small, with proper moon, and long runtimes on low, i hope when those that haven’t jumped in yet will see that, they will be exited enough to pull the numbers to get the lower price & copper 
I am almost hesitant to ask, because i know it is a lot of work but some runtime tests i guess is needed anyway to tune/test the LVP.
@Dale which djozz’s springs are you talking about? the ones he had made in phosfor bronze and is diameter 10mm, height 15mm?