I haven't seen a Twister kit, but on a Skyray the tabs on the back of the ribs substitute for the jig. If you wanted to use a rod type jig to build the wing, all you need to do is stack the ribs and drill holes outside the cutout area, ANother alternative would be the leveling bar system used in Brodak kits. When I first saw it I was doubtful, but my Shark 402 wing came out really straight, and the method is a lot easier than the instructions made it sound.
cheers,
Ken