I decided to go with 1.5 x 3 x .120 on frame connectors with the box style at the back. I was going to go round tube like HemiDenny did, but after looking at it, I really don't have anything at the rear to connect like he did. Plus.. I just happen to have some 1.5x3 laying around :) . I've got some 2x3 but it's 1/4" wall and heavy af. The 1.5 will be fine...