If I tried this method my clients would have a cow. They would prefer the work be finished professionally and in a way that will last. If I can't find matching thread in the correct weight, I double the thread in my needle of the matching lighter weight thread which usually matches tthe original thread. Furthermore, if somebody is looking that closely at the zipper area of your pants, they need to be slugged. This article is not up to your usual standards, I hope this is not a sign of things to come.