Yessir miked, it shall be done, and many thanks for your good words, with thanks to everybody else too. This will be a retro-style build, recalling those thrilling days of yesteryear when 2 other guys and I ran a little sound company. Really all I did was supply the money and was otherwise along for the ride, albeit supplying muscle as well when we deployed in various venues.
Our full-range cabs were factory JBL 4663s (Perkins bins with a very nice cast aluminum compression horn for midrange and a 2405 for tweet), 8 of them. We covered them in black slate Formica and put aluminum extrusion on the edges, and it did add much to their roadworthiness. Bottom end was some double 15" "sugar scoops" and some vast double 15" horns, those things were big. All factory JBL. Power amps, mix, and crossovers were all Yamaha with BGW for backup. None of us knew what we were doing, but by accident it sounded OK for its time. We could handle venues up to about 1,500 persons maybe. Got to meet some nice folks, and some real jerks as well.
Anyway, to recall the glories of the past, such as they were, these cabs will be covered in black matte Formica, with DuraTex on the front behind the main grille. Haven't decided whether to use cloth for the grille, already in hand (MelloTone) or get Penn-Elcom to make steel grilles. They make grilles of any size to order. I'd like to go with the steel but not sure the funding is there

, and also not sure about the sonic transparency of the steel grid.
Then they'll have aluminum extrusion on the edges, and those big steel ball corners, probably the stackable ones, although I do not foresee ever stacking these things.
OCD you see, as miked pointed out. As for filling the holes in the braces, well, there were the holes, and there I was, and the goo was close to hand, so... why not? I didn't like the imprecision of the screw placement and thought filling the holes might help, and it did, a little bit, to my eye anyway.
Anybody have opinions about using polyurethane spar varnish on the inside of the cab? As a sometime dweller near salt water I always like to seal things up against humidity, so they don't start changing size and shape unpredictably. Are there any drawbacks to doing that, other than time and cost?
Thanks once again everyone, this is great fun, good occupational therapy too, and is teaching me a lot.
Best
--aeolos