Over the past week I've been accumulating my supplies for my diy hammock/tarp. Everything is pretty well in order except for a few tarp questions.

First of all, I just intend on making a 10x12 rectangle tarp. A nice tutorial would be excellent.

I'm wondering about sewing the reinforcements mainly. How different are the side reinforcements than the corner reinforcements? Is the ridgeline seam sewn with grosgrain? If so, why?