This was actually an 8x10 flat tarp first but after a couple gusty trips I decided I wanted a tighter pitch. .75oz cuben. Final weight is 6.6 oz. sides and ridgeline have about 4" deflection and about 2" per half on the front and back. I used 1/2" 9485pc on the edges and ridgeline, then used hysol to bond a strip along the ridgeline and also for the tieout reinforcements. The first time around I used all cuben tieouts similar to Dan Durston's tent fly (rolled into four layers) but because they were sandwiched between the body and the reinforcement, you end up with more peel stress than I liked on the ridgeline tieouts. Here I just went with grosgrain sewn to the edges, which seems totally bomber (I had LOTS of layers to sew through because of the previous tieouts). It will be for two people, so I wish I had made the original width 9' or so (8' is fine on a flat tarp, but wider at least in the front would be nice for a shaped tarp), but overall I'm very pleased with the finished product.

Great Job Brendan! Do you by chance have a picture of your ridgeline tie-out up close?
thanks

I'm also planning on adding grommets to the webbing...

That is really nice, I'm thinking about doing that some day

So, the ridgeline is 10 feet long with a catenary curve that has a 4 inch deflection at the center? I think that's what you said.

And you attached the two pieces along the ridgeline with hysol? And added another strip of cuben with hysol?

Correct; 10' ridgeline with 4" deflection at the center. Same on the sides. I used Roger's spreadsheet to do the curves. I taped the center ridgeline first with the 3M tape and then bonded a strip of cuben over the top with hysol. I think it would be VERY difficult to do the curved ridgeline with just hysol, but it's pretty easy with the tape (I used 1/2").