I Think I've posted this before. I got a piece of 2x2 square aluminum and took it to the guy that was building my trailer. He made the rack for the tracks from that by adding a plate to the bottom of each piece and drilling the plates for u-bolts. I lined the brackets at the top with a piece of carpet. Made it a little tall, but it later worked out perfectly to add a borrowed, plastic, locking truck box between the stands for additional storage. Cheap and purpose-built. More pics if you want them.