yes, it doesnt matter how you put it together, if the fron overlaps the sides or the sides overlap the front, most tanks are built with the sides overlaping the fron, look at any tank you have at home and tell me how they do it...
given the fact they you want to have the side braces overlap the lengthwise ones, then just make the top ones 23.5" long and the bottom ones 19.5" long, the tle bottom ones are sitting flush, and the top ones are sitting on or under or whatever... i would have the cross ones(bolth side and cross)flush with the top of the tank and the front and back ones 1/4" fron the top, just under all 4 braces...
god i hope i didnt loose you there.