I'm grateful to all for the comments. The comments have been very instructive. I've since ordered a variety of straps, clamps, fasteners, plates, thread-lock compounds.
On the lighter side, how can my photos not improve after all these added gadgets?
Every hobby I've ever had (boats, fishing, golf, woodworking) builds an industry that convinces you that you must have "one of these" to stay in the game.
I'm a sucker for "a better way". The BR with clamp will be a better way.