Belatedly, I was looking at LEDSupply’s triples (serial) and searched and found this thread.
Anyone using these 
or these? Cree XLamp XP-E2 Color LED with
that boost driver Tested CNQ Boost driver (Luxeon Triple in series)
and one cell? I’d thought that was impossible, now I’m tempted.
Or, I guess, pull the resistors and wire the triple as a parallel, but mmmmessy small wiring work.