Okay, I am getting ready to purchase the metal for my trailer frame and I did a theoretical weight of the steel and am surprised by a few things.
First off, I have seen discussions around 2x3x0.095 retangle being the same weight, but stronger than 2x2x0.120 so I am leaning toward the 2x3x0.095. I am doing flexiride torsion half axles so I can make the trailer the width that I want (overall box is 5' by 9'). As such I am going with a 3x3x0.120 "axle" cross member. I am also going with a 3x3x0.120 tongue. Then I got to thinking, why not make the whole thing out of 0.120 wall tube.
The weight of all components at 0.120 is ~285lbs, the weight of all components at 0.095 is 228lbs for a difference of about 60lbs.
I was surprised that the trailer frame was so light (only 285lb). and In the end, do I care about the 60lbs from the thicker gauge? I just "feel" safer welding thicker gauge metal. Might be way overkill, but 60lb doesnt seem like much to be concerned about.