Riveted the stiffeners using Van's suggested technique of back riveting. I chose to not install my Avery back rivet plate into my table. I opted instead to sit it on the table with a thin rubber flooring mat (could have used carpet instead) on each side of it. I've done it both ways, and I like this method better because you can move the plate (and mats) around to get the best angle and comfort level for each row of rivets.