Yes i have used them. It's a very good idea. You can use a lit match to both melt the solder then shrink the shrink wrap. It's fast quick and easy. Hobby shops carry them. When I use them, I use one of those small hand held butane torch's and it makes it very fast process. I should add that the bigger ones you should use the torch. I'm glad you posted this cause I lost my buying source.
Retired Anesthetist. LTP. Pilot with mechanic/inspection ratings. Between rigs right now.. Wife and daughter. Four cats which we must obey.