I had previous layouts with cheap wood, and one with particle board. This time I took the good advice and did the whole thing with quality materials, and I'm very glad I did!
That whole bracing box is attached with Loctite PL3x adhesive. If you haven't used PL3x, it's amazing. It was recommended by @Tom Tee, and I swear by it now, really good stuff. The only precaution is, don't get it on something you don't want permanently bonded! Once it cures, the only way to get it off is chisel it off. If you bond two pieces of wood, trying to separate them will pull the wood apart, not the adhesive bond!
Tom did the corner braces before he brought that bottom bracing framework up, so the corner gussets "may" be secured using Titebond III glue, also a glue that once it's dry will take the wood apart trying to remove it! We glued it to the bridge top with the PL3x and a few power brads to hold it in place while the glue dried. The bridge is one piece now.
