Run Rafters. Came up with this idea from a variety of other devices. It worked as my run is only 8 feet wide, not sure it would work for larger structures.
More info on my coop page but here's the basics of the concept.
3/4" EMT electrical conduit clamped to T-posts. Clamp is 2" PVC with 1/4-20 T-nuts inside, screw tightens against base of nubs on T-post.

2" x 4" x 6' 14ga wire welded fencing clipped to T-posts and wired to EMT rafters set at 68" spacing.

More info on my coop page but here's the basics of the concept.
3/4" EMT electrical conduit clamped to T-posts. Clamp is 2" PVC with 1/4-20 T-nuts inside, screw tightens against base of nubs on T-post.
2" x 4" x 6' 14ga wire welded fencing clipped to T-posts and wired to EMT rafters set at 68" spacing.