Deed is done, theory worked out! Very solid with one bolt.
Turning the bars? Well, not what I purchased a rack for, needing to readjust a pretty well tuned bike every time I take it off the rack (will use this for non-RV biking also). These are better bikes, and while not hard, is not as easy as a simple allen wrench, either.
More importantly it was all about the bounce. Slamming up and down for 1,000's of miles just has to lead to stress failure of something. Now that it is all clamped, the ride in the back should be much smoother. And clearance from bars to window is excellent, and should stay that way!