Our new-to-us laminate jib is starting to fail along the edge of the sun cover; the cover makes a stiff spot and the flexing is damaging. The cover was also too small and is itself, failing (UV Insignia cloth). If I tried to sew on a new cover the needles holes would destroy the sail, and it's too old to justify the expense and effort, really.
If the ONLY thing we want to due is block the sun, why not paint? For the past year I have had samples of many different paints, ranging from house paint to specialized sail paints on racks on the roof, weathering. Naturally enough, it is a writing project.
I did a few minor repairs first. Yes, the strip tapers; you need more width at the clew than the head. Normally I hate mini-rollers, but a 4-inch foam roller is just the thing for painting a sail. Pretty easy.
FYI, the sheets under the sail are there to protect the sail from the asphalt more than to keep the paint off the driveway.
Another advantage of paint is that it is light. I don't care about the effect on set, but I do care about the extra weight flogging against the vulnerable leach fabric. None of the sailmakers recommend Sunbrella, for example, on laminate sails. for this reason.
Although the roof top exposure tests are not complete, I selected MDR's Inflatable Boat Topcoating. It seemed to be among the top performers, I've used it on inflatables, it got a top rating from Practical Sailor some years ago, and I had enough left over. Free is always nice.
No, I don't expect it to last as long as a Sunbrella cover. Neither will the rest of the sail. But it also cost me only 15 minutes work and $15 worth of leftover paint.
Look for a detailed report and follow-up in Practical Sailor Magazine.