I want to incorporate a tool box, battery box, and places for fuel jugs in the bed of my truck when I build the bed cage. It would be much easier for me to build these boxes out of square tube. The boxes will share tubes with the bed cage. Design is based around fitting a dirt bike on either side of the tool box (tool box will run front to rear of the truck, rather than side to side).
I also want to have points in the bed cage where tubing can be sleeved for a bed rack, for a roof top tent.
Assuming good geometry (redundant and equalized), is there a significant reason to not build the bed cage out of square tubing?