I came across this option for working with super telephoto lenses that I wasn't aware existed. The use of a monopod with a monogimbal head. It appears to offer stability and versatility without the long setup time and weight of a tripod. You add a long arca swiss plate to the lens mounting foot, and attach that to the monogimbal. The monogimbal works like a standard gimbal in that your lens is balanced and dampened, but has some advantages, such as being able to point the camera farther up or down (since it is offset to the side) and not being so bulky. Your lens needs a rotatable tripod collar in order to use it.
When walking around, you can carry it like a rifle and most of the pressure goes onto your back rather than cutting into your shoulder. The camera is immediately available if wildlife is sighted.
Wimberley makes the MH-100 head and sells it for $180, there are also copies going around for about $60 that are said to work similarly well, as long as you don't use the 3/8"-1/4" adapter. Wimberley also makes the P-40 long arca swiss plate with two screw locations that you may need to attach the lens securely.
Reviews are quite positive and the user pictured is satisfied and happy with it still after 5 years of use.
I'll be trying out this technique with the Canon New FD 500mm f/4.5 lens soon. It's 6 pounds and I knew I would need to find a way to make hiking with it less exhausting.
