I have watched Steve Perry's video on gimbal; I don't think a gimbal would be in my budget right now, but I do have a ball head, and he showed how to do an add-on to that which will help.
I also researched the Blackrapid straps, the Sport Breathe being an interesting one.. Because I often use a mono or tripod (Manfrotto w/quick release plate), I don't want to remove a strap during setup, too paranoid of having the gear with no support for even a few moments (and I also like their optional safety tether to add onto the system). There was a video I saaw on line last evening describing the 3 Legged Thing L-Bracket that is a universal fit, and allows the strap to be attached to its side while keeping the QR plate attached to the base of the body. That sounds promising; doesn't deal with long lenses where I want the QR plate on the lens, but understand that support from the foot of the lens is a preferred method for proper weight distribution, in carrying, and mounting on a pod.
I've always done well with a strong neck strap (I have a custom Souldier strap), but have not gotten much into heavy lenses before. The Tamron 70-200m seems fine with just a neck strap, and I can mount to a pod from its foot; the lens does not appear overly long/heavy that poor weight distribution to the camera mount is an issue. Not going to be the case with a bigger piece of glass. If a limited day rental, I think I can get away with a second strap connecting to the longer glass, giving needed support (and taking away the strain from my arm), but the right combination on something such as Blackrapid is something I continue to consider (I wrote them with my overall questions and recommendations, their responses seem good, they made an initial recommendation to me quickly, and after the holiday weekend expect them to address my next questions).
Thanks for the responses on all this....