Andrew and KC, I agree with you both. Regardless of design or weight or tubing dimension, would you rather buy a trailer with a 1/16" tubing tongue, 1/8' or 3/16"? Would 1/4 x ? tubing be too much for a #1000 trailer 13 feet in total length? with an 8' cabin and axles at 62% of the cabin length? I am not going to do the math. I know from experience strength and durability is achieved with size, thickness, shape, design and execution.
My goal was to build heirloom strong and as light as possible. Weight equals dollars. Strong, light, cost effective. 4 x 4 x 8 #1000 Beauty for me.