Hi Bill - Thank you for suggesting the sidekick ...now that is a price I can live with and I like being able to keep my ballhead in place! Someone on Amazon uses it with a Nikon D-810 with the Sigma 150-600mm Sport lens and he gave it 5 stars. Maybe I should trade my P-20 lens plate for a P-30 that Wimberley recommends for this lens. I don't know if it really makes that much of a difference but you are correctly Bill, it will be zoomed out to 600mm a vast majority of the time as was my 100-400mm at 400mm.

I am waiting for B&H to refund me for a ASUS monitor I returned due to dead pixels, as soon as I get that I think I will use it toward the Sidekick. I think it will be the perfect choice for me. I can't justify spending $500+ for a little as I will be able to use it on the weekends.

Thank you for all the suggestions, it gave me a lot to consider and be made aware of for when I do start using one.