I've attempted to attach the sketch up file, it's zipped up so it will need to be unzipped to view it.
For the square tubing, I used 2" square by 1/8". For the A frames, the measurements were 40" for the long pieces and 22" for the cross pieces. The top cross piece is flush at the top. The bottom cross piece is 4" up from the bottom. I used 1.5"x1.5"x 1/8" for the angle to tie the top sections together. This gives a total width for the workbench of 22" + 2" + 2" + 1.5" + 1.5" = 29"
For a tool box section, I spaced the A frames with inside measurements of 40 1/4" The front lower angle that the toolbox sits on is flush with the front of the a frame and the bottom of the angle where the toolbox rest is flush with the a frame cross piece. The back angle is spaced 18 1/4" from the front angle.
For the sections between the tool boxes, I made them 2' wide on the inside between the a frames.
The holsters are each 1' long. I used a 2" hole saw 4 1/2" from the end and cut a circle, then used a sawsall to open it up to the end.
The drawer slides I used were 24" long 18 ball bearing slides from home depot. I used self tapping screws and small bolts with lock nuts to secure them.
I used 3" 1/4" ******* for the air tool slides, cut them in half with a sawsall and then welded them to angle.
For the two shelve sections, I basically took the length that was left after the 3 toolbox sections and the 2 cubbies and split it for the between support. I used the angle on the toolbox side and the back to create a lip to help contains things rolling back or to the side and reversed them on the front and outside to make it easier to slide stuff in.
The top is just 3/4" plywood. I pre drilled the top angle as well as the inside back tool box supports to take 1 5/8 wood screws.
Hope this answers most of the measurement questions.