Here are the pics I had handy.

This is the table on which i weld frames for theatrical scenery for Cruise ships all day long.

The table is 5' wide by 18' long, the grid surface is 1' on centers lengthwise and 1'-3" across.  The outer perimeter is 1.5" x1.5" 11 ga. box tube, the inner members are 1x1 11ga.

The current fence is 2x2x3/8" angle...the 1/4" fence in the photos got too wavy.

As far as height goes, I built it so I could easily reach the center with my feet flat on the floor.  About 3-4" below the surface is a layer of 1/4" lauan that keeps sparks off the stuff underneath it, and serves as a resting place for clamps and small c
In use, the parts are clamped to the crossbars where they cross, and joints are either clamped to the bars they land on, or clamped to each other in space.  Small blocks of scrap Aluminum and steel serve as clamping aids to help when different sizes are b
When parts get too small for the grid, I have a smaller grid of 6x6 squares I can drop on top.

Under the table on one long side is a two level rack (plus floor) for 'kits' that have been cut and are awaiting welding.  On the other side are shelves for things like caster plates, buckets of chain, welding blankets, my hossfeld bender, pipe fittings a
The feeder (which is basically the wire feed motor and control circuitry, a solenoid for the gas, and a power wire) is free swinging on an arm about 8 feet long set at about the middle of the table.  With a 15' stinger, it reaches the entire table plus a 
If I did it again...which I may get to do soon, we've outgrown it...
The bars would not be on any common center, it is easier to use without the joints landing on the bars, and less chance of welding a frame to the table.  The storage racks would have a bunch of 1" lengths of tube sleeved over them so 'kits' would slide in
Any questions, I'll be happy to try to answer them.

Stuart