He merely mentioned an MCU. So I Google MCU.

This looks promising, but difficult to figure out and get set up with all the tools:
Zilog Document Download So, I recon, based off past experience of 85% efficiency, that in real life, 425 ma is 10 hr, 530 ma is 8 hr. 700ma is 6 hours… 350 mais 12 hours… 1000ma is 4h 15 minutes. 100 ma is 42 hours, 30 ma and 10 ma desirable
Desired ma levels in decreasing order of importance 425, 530, 700, 240,350,100,30,10 ma.
This is the closest board to my dream, but no mention of getting 8 modes of various percentages in the pdf. Steep learning curve and equipment to buy, I bet. Complete with 2 days worth of snags?

I just got tired and sick of it all, so built,this last weekend, a 2x amc7135 + 1 amc7135 (all 350s), 2 switches. Unfortunately, it runs only 6 hours at 700 ma before dimming. So, 85% of expectect runtime, 4250 mah are available for use, using the amc7135. …I want another build, the hassle of clicking between modes is not going to cut it for my guys. I have only had true love for the dimmer switch, but could live with an 8 mode light with these steps, on a 21700.

Got an email this morning. Looks like the LiS battery is a few years off still. Something about their physical size. I know that they swell and contract, which is no big deal for a headlamp.