I am shooting from blind, taking in consideration small "window", limited movement right and left, monopod is more convenient, gimbal is giving me easy to use support. In some situation, in different hide I am using tripod with gimbal. TC was added just for testing and with only small birds(no raptors) present, gaining some experience. Will see...
My previous set was D750 with 200-400+TC-14 and quite often nesesery shutter speed was in range of 1/1000 sec.
Also that was really my second session with this lens, will see...
I hope I did explain my rational-if not, next question, please!