My basic plan was to use 2 lengths of 2" square tubing with 3/16" wall to span the two I-beams of the trailer frame. I was going to weld some 3"x3"x3/16" angle iron about 4" long on the ends of the square tubing to be able to bolt this to the I-beams. I want to bolt them because my trailer has the polar package and I want to be able to remove the hitch system in case I need to remove the coroplast to get in there. I was then going to weld a length of receiver stock to the two spans of 2" square tubing. Basically I will have two full lengths of support and both will be bolted to the trailer frame. I think that will be more than strong enough.