Hi, I've been out of the camera game for a few years, strictly digiscoping, but I was greatly pained last week not being able to shoot a couple jaegers in flight, that I really wanted. For the moment, I just want to stay pretty cheap. I'm thinking of picking up a 400 f5.6 and some body, both probably used. In the past I had a 7d MkII, but I'm thinking maybe I don't even need that for now. 1. Is that the right lens, and 2. what body would you recommend to get by with. Ultimately I imagine an R7 and possibly the 100-500 if it turns out the autofocus works well enough on BIF. But I don't have the 5 grand right now, and I want something ASAP. Thanks