You could try a 0-100% Q5 from DX, if you don't care when you get it.
I've been 'waiting for supplier' for about a month.
The Solarforce 1 Mode R2 dropin has a reduced output of 150 lumens and can go for at least 3 1/2 hours on an 18650
I was being generous with the 18650 number. A 17670 can go for about that much while an 18650 can go for 4 hoursThe OP should note that an 18650 cell does not fit in a stock 6P. If you want to use a 3.6V drop in 17670 is your best option.