We used to soak the meat just like that when I was in South Dakota. It helped to pull some of the sage taste out. Never needed to add sage to venison out there, except for breakfast sausage. Adding the vinegar helps to tenderize the meat by breaking the protein chains, which has the same effect of aging(letting it hang). Here in the flat part of PA the deer eat like cattle do, feed corn, apples, primo grain/grass and any thing they can grab from unfenced gardens. In my opinion the meat doesn't need to soak if it's rinsed repeatedly, so why make more work for myself.
I made soap from the tallow last year. It was a heavy weak lather soap(like bar laundry soap), but my wife said it was the best dreadlock soap she ever used. I therefore will be making soap from all future kills, to keep my hippie princess happy. I save a good amount of the bones for use in various projects, along all the sinew as I can find and I'm making rawhide as we speak now. I tried to make hide glue from the bone broth last year, but wasn't pleased with the end result and tossed it. I'll have to review the procedure again to see if I goofed.