Prior to attaching the U-bolt, I first widened the radius, and as I tightened the bolts, I was careful not to over-tighten
them. Also, beneath the bracket, I made a couple of wraps of electrical tape so that the bracket would have something to grip and
to "bite" into, without tearing up the paint or denting the tube.  The hardware is Nylock, and is made for 1" tubing. (Motorcycle
handlebars, ostensibly.) The tubing on the Scout is 1.25", so I had to also be careful of that. I ended up recessing the holes in the bracket with an endmill, because with the greater radius of the U-bolt, there wasn't much thread  left over to work with. The bracket itself, is 1/2" thick, so I recessed it 1/4", and attaching it was no problem.

Frank H Weeden