You could use a Taskled driver; B3flex for 3 LEDs or HBflex for 5 or more. 4 is gray area, probably H6flex 2s2p. A 3A Sharkbuck from Sandwich Shoppe would also work for up to 3 LEDs and I think they can be paralled for more. I’ve been playing with 105C drivers and have been able to mod one to run 3xml in series from 12v supply. See this thread.