One thing I'm having trouble understanding is why you have a continuous ridge line over the tarp. Is it just so you can tie prusik knots in order to have the ability to slide the tarp from side to side? I tied my tarp simply using a short length of Nite-ize at the end of each tie out. Basically the "knot method" shown here:
To adjust the tarp between the trees I loosen one end and tighten the other. I can see how this might be a little easier if it were fixed to a line with Prusiks, but you would still have to adjust at both sides.
I get why you might want a ridgeline under the tarp...but what is the point of over? Thanks for helping a noob understand.