I don't know if this is still the best way to do it, but it was in TTK. Pop a 3oC, and go to The Dreadnaught. Kill Ultra Knight. Leave to orbit. Change characters. Repeat, changing to new characters each time, cycling your three characters. Each character has their own invisible cooldown on 3oC making drops more rare (but not impossible). Rotating characters like this [i]should[/i] run the cool down on each character by the time you get back to them.