Thanks, and you're 100% correct; it's Uni-Strut. The legs are made of square tube with a plate cap on the bottom. They sit on the factory roof rails, and have holes in the plate so I could use the stock mounting system. The front legs are just stainless threaded rod with 2" soft rubber bumpers on the bottom to disperse some of the rack weight on the roof. I tapped a hole where the rods are on the rack, and used lock nuts to adjust the height and tighten.
If I had to guess, it probably weighs somewhere around 60 pounds. The expanded metal is the heaviest part.
The contour to the body was actually a mistake that turned out cool. The 3/4" square tube crossmembers are notched into the bottom of the Uni-Strut, and when I welded them, it closed the gaps in the notches up a little, causing the whole rack to pull in that slight curve...I can't take credit for the idea, but I can for the mistake!
The rack is very strong. I've stood up there numerous times to load and unload things. It will flex a little if I'm standing in the middle, but not enough to touch the roof. I've had it loaded down with a 4x8' sheet of 3/16" steel with no issues!