I called up Vally Iron today. They don't carry DOM, just regular mild round tubing. I was quoted at
$3.60/ft on 1-3/4" x 120 round tubing. Levvi carry pipes only. I guess I can go with the 1-3/4" for my exo -cage.
Like everyone here would agree...it's more important to focus on the design and the welds themselves rather than on the fancy materials.