I guess I'm just a lazy b@st@rd. I take a whole spool and run a pack strap through it. That gets used like that until it is almost gone, then the spool is replaced. It is out of the way but handy to grab and tear. Then I let go and don't think about it until it is time for the next marker.

That's worked for me for decades so I never thought further about it until your post. Very clever. I wonder if a chewing tobacco tin carrier might be wide enough for a partial spool to fit in.