Originally Posted by nothermark
One other issue is to leave 8-12 in at the back for air to move in. If you set up with the back to the wind and a space at the bottom the circulating air will push smoke and sparks away from the tarp instead of under it.
Dave Buckley also used to promote a tarp with wings. Basically cut a piece of fabric on a diagonal and sew one piece to each side of a tarp. The wings can be significantly lighter and not water proof as they are used as a wind block pitched vertical or close to it. He pitched it with the edge at the edge of the fire so one could sit under the tarp and feed the fire or cook over it.
I looked at the Swack Shack- I'd be tempted to cut one down to 5x7. That will handle 1or 2 folks. Take two for a party of 4. ;-)
Did you check out the BCUSA tarp (link in OP)? I think it is the same material but comes 5'x7'.