Been watching lots of videos! This site is so great for that.

Tying off on the tarp's D-ring would be an easy way to do it... but think I would like the option to remove the tarp, which the Dutch continuous line offers, courtesy of soft shackles prusik-knotted to the line. I could also use snakeskins to keep the tarp out of the way in case I don't want to use it, and I may go that route, though I'm currently stuffing the whole mess in a bike seatbag to transport -- snakeskins might just add bulk I don't need.

Lots of tinkering and fiddling ahead. Can't wait!