Imade my own jigs.Go to Lowes and by 90° extruded aluminum. Cut them into 1" sections. Use a bandsaw, hacksaw, or chop saw to cut them. You can drill a small hole in them to put pins in to secure them in place. Them simply place the piece next to the rib, pin it in place, and put a small clamp on it to hold the rib securely to the aluminum piece. For less than $10 Imade about 50 or so, as best as I can remember

The ones Iuse have been converted for a magnetic building board, so you can see the magnet on the bottom of them. But you get the idea from the picture