I used red cree LEDs and green cree LEDs. The red ones had a forward voltage of 2.7V so I used a 3.3V UBEC along with one 1n4007 diode in series. For the green, they wanted 3.2v so I used the same 3.3V UBEC and just tapped off before the diode. Sorry, no pics on hand but works well and saves lots of stuffing around. No heating problems, after 5 mins LEDs are still at or just above ambient and that's even with being covered with clear heatshrink.
A silicone diode drops between 0.6 and 0.8v across it (depending on current). It's a wasteful way to do it (converts into heat) but is simple and light weight and compared to the amount of power used by the motors on a multicopter is really negligible.
Here is what it looks like:
View attachment 12865