Last summer I put together a GrizzBeak, made from cuben fiber, to be used with a (then) newly acquired MacCat Delux in cuben. It was all pretty straightforward so I didn't figure it warranted a posting, but here russmay pointedly asked for details, so here they are.
I have some CT2K.08 in olive, roll width is 54". This pushes the template to have either the front or bottom edge be 54". It worked out that both were, with a 6" overlap at the top. Here's a template.
I rolled the edges everywhere and ran a stitch to hold them, except where the two pieces of the beak come together. There I used double-sided tape I got from questoutfitters.
To re-enforce the corner attachments I bonded and sewed into the rolled edge a small bit of 1.9 oz/yd nylon. I made corner tabs from grosgrain and
attached at the edges with a single bar-tack (although there are stitches to hold down the grosgrain along the tarp-side corner, they aren't holding much.)
Packed down the beak has the volume of about 2 decks of playing cards, and with the cord at the corners comes in at 2.25 oz.
It's a nice light addition to the pack that gives a lot of protection from wind and rain at what would otherwise be an open end of the tarp.