Thanks for the explanation on the brace. I'll have to be sure to only add them to the sliding end of the bridge. I'll also need to make sure that I orient them in the correct manner at installation time.
I just drew up my next set of patterns for etching. Lattice work for the verticals and top of the structure. I haven't decided whether I should etch the "dog bones" that run along the bottom of the four center panels. They need to be about .015 which could take quite a while to etch. I have never tried anything that thick. Maybe I should try putting the pattern down on both sides and etching from two directions. Might be interesting!