I wouldn’t use 5/8ths for the ends or center since those components receive nails in only in their edges and not through the face of the ply. There may be a tendency for misses when nailing or for these components to split otherwise. I’d even be wondering about the sides for the same reason.
Hmmm, also, I guess if you were planning to use fin nails then you would be forced to wonder if even the top and bottom faces wouldn’t be in danger of coming loose at some time for lack of meat to be fastened through.
You might want to check your cut list to make sure that the loss of thickness doesn’t force you to use up more sheets when you have to cut larger ends, centers, and sides.
Remember that the ends and center are all cut the same size (two sheet thicknesses smaller in each dimension than the finished box.) The sides are next and have the same reduced height as the ends and center but are full length to overlap the ends for nailing. The top and bottom are cut to the full dimension of the finished box and cap the sides and ends.
When deciding where to put the holes you might want to make sure that your intended crew can safely and effectively carry around four boxes at a time instead of two even with your +/- %16.5 weight savings per box.
Also take into account the increased deflection in the thinner material when a tripod leg happens to be placed in the weakest part of the large face when instructing your camera people on how to use your new design.
To put it in industry terms I might say something toxic like: “Come to think of it without a team of engineer’s and experienced union carpenters around why would you guys be messing with something that has worked for like a hundred years.”
Especially when humans are apt to stand on the things.
I guess it might save the planet?
or $5?
Actually after my years in the industry and the time I’ve spent watching the kind of crap it’s largely responsible for it might do the planet more good if we just shut you guys found something productive to do like shovel the f’n snow or fix a little old lady’s roof.
Ha!