I've always preferred the tarp be draped over the line rather than suspended from it with ties or fasteners. It seems a lot more sturdy and secure when draped, and any leak problems are fairly easily addressed by a simple drip line. I've done everything from canvas to nylon to woven poly that way, and find that putting some tension on the tarp makes it less prone to riffling in the wind.

I've had a few bad experiences with ties in foul weather where the ties ripped out of the tarp. Same with lacing grommets along the ridge line. Under more ideal conditions that may be the way to go, but I will no longer do mine that way.

Better still would be to have a ridge pole, but that isn't often very practical.