in the campground, and it was a Kelty 12' tarp. One of the main ends was tied to the top of the A frame and the 2 adjacent loops were tied to the handles on the A frame just down from the apex of the A frame.
I asked the camper about it, explaining that I had an A frame, and liked the looks of what he had set up with the Kelty. He said it works very well, and they have various sizes.
The Kelty looks like the best of the "compromise situations", although some tie down places are needed, and/or poles. It can be modified for various situations, and I am checking into a purchase.