Another good one Shug!
I was tinkering with reefing yesterday. I ended up tying a long line outside the prussic on one end and then reefing the tarp with a series of half hitches about
every 18 inches as I moved along. This worked well, but a reefing line from each end, or two from the middle may be a little easier to work with. It's kind of like sheepshanking a rope, only with the tarp.
Sorry, didn't get any photos, but I will soon if needed.