BioMax
+1y
WOW! 2x2x.250 is some really heavy duty stuff!
You can use .065 wall if you do it right. The trick to support the tube where the stresses are applied. Don't run a crossmember across a 48" span and then attach a link-bar to the middle of it. Use 2 smaller tubes to support the crossmember at or as near to the stress point as possible.
If you notice how I supported the .120 wall cossmember in the pic below, you can get a better idea of what I am talking about.