Just so folks understand, the use of the in-bumper anchor pts, with a structural member attaching one to the other, is primarily for fore/aft stabilization of the receiver tube mounted upright. The stabilizer straps (2 of them) would go, one each, to the leading edge (and corner) of the trunk, with, say, a 3"wide 1/4" plywood strut connecting the two trunk-leading-edge vinyl covered "hooks" to serve for transverse sway stabilization. The plywood strut would be necessary so the hooks don't migrate towards the centre of the leading edge - when under tension. Alternatively said vinyl covered hooks could go to the vertical / "down-comer" trunk edges... and then they would not migrate. But used on the leading edge (and notably the corners-) of the trunk the forces in the straps would "resolve" into both fore/aft AND side-to-side stabilization.
I believe my arrangement would indeed be stout. Also, the receiver tube would cater for my utility trailer 🙂.