The original upholstery and the recover kits come with "u" clips rather than hog rings. They clip the material over the edge of the frame. Pretty easy to install with a pair of pliers with some leather around the jaws so the teeth don't damage the vinyl. Jim Carter sells these individually
Here or with an installation kit
here.Anybody who's reasonably handy could do the job. I did mine over a period of 2 days, including stripping the old stuff off, repairing a couple of spots and painting the springs, then installing the covers.