Count that as a fourth request for a reliable source of food safe heat shrink tubing! hehe
I use pipe bits on all my pipes, and am fine with them, though on a few of my smaller pipes it was a constant battle to keep the stem from slipping out of the bit while in my mouth. And I had it pop off and into my mouth a few times, almost choking on it! hehe Not exactly a relaxing trip to the deck with my pipe.
I ended up getting some 3/8" black latex tubing and cutting my own for the smaller ones...they work fine but they do have a ridge on the cut edges that is kind of uncomfortable on the tongue...the heat shrink might do the trick!