The first one of those I did was probably 10-ish years ago. I was meticulous in fitting the patch perfectly and clamped it solidly, as if it were a backing strip. I couldn't bear to fit anything that wasn't absolutely perfect, as Dean's article recommends against. Soon after, the patch started to crack along the glue joint. I showed it to Dean at a rendezvous, who told me the feathering angle was too severe and that my clamping starved the glue joint. He said something to the effect of, "This is the only case where sloppy craftsmanship pays dividends." I listened to his advise and have done several more of those patches over the years, exactly as he describes. All have held fine.