Summary

This should speed up the process of making the loop for the string. The simplified, 1 piece version seems more practical than my early multi-part version.
The gap is only /3mm, so scale up if your printer isn't the best. Sandpaper can clean it out also. The hole is for the string to attach so it feeds thru as you move along.
Maybe a lurker will get UOHA and participate. Stop being an npc!
Again...here's the Orchard link in the hope of one of the npc's actually doing something, poke, poke.
https://3dorchard.com/app/single/5865c94e5fa09b0c8fd1f18a/5beb2123fbd4ac0bb24e10cd

The boat shrink wrap (Polyolefin) is an amazing material that could be used for sheds or car covers. When it's done right it can withstand very harsh weather.