Resistor bridging is a bit risky... I'd go conservative on adding resistor(s). With keeping the driver, of course, you would keep compatibility for more than one cell, and all the other driver features. My idea of sandwich'ing a Nanjg driver would restrict it to only one cell.
I got a SupBeam L6 (review: https://budgetlightforum.com/t/-/26046), and do like feel of this size 26650 lights in the hand, plus the advantage of using higher capacity cells. The Warsun's will cost more, but sounds like they are a little better quality too.