Good stuff Aaron. I was talking to my Consultant this morning, whilst having the injection in my shoulder. She's a keen wildlife photographer, and it was her who suggested getting the chest harness, to ease the strain on my neck and shoulders ( having described it, she now wants one!).
She uses Canon equipment, including a 400mm zoom, and perhaps I should have gone down that line, rather than Nikon, as I understand their zoom lenses work on the 'push-pull' system, rather than the 'twist to zoom'of the Nikon/Nikkor lenses, a bit of an advantage for aviation photography in some instances. I've missed some good shots when adjusting the zoom, but some of that is down to my stiff hands, I admit.
But, although my own film cameras were Olympus, I'd used Nikon extensively too, so went with what I thought I might be familiar with. Now that I've re-arranged the two pistol grips on my shoulder stock set-up, I might investigate using a collar and handle attachment, if such a thing is available to fit my lens focusing barrel,and won't foul the rail mounts, to make rapid adjustments easier.
Heck, any more additions, and I'll need a truck just to carry the equipment - and look like an MGM wannabe into the bargain !!