This time I decided to fit the cross dowel horizontally because I was worried that otherwise the extra lamination could split when the bolt is tightened.
I silver-soldered a brass square onto the cross-dowel to keep it from turning away from the bolt.
Silver soldering 3/16" x 1/2" brass tension hoop.
The first joint failed, and so did several more.
The final joint has been strong enough to hold up to a lot of bending and adjusting, so should be plenty strong under tension.