You might even want to consider a setup like I had before I got my full enclosure.
It was a canvas cover I was given by BWY when I bought my boat. It was surplus from their Mac Cat.
Basically a rectangle with tubular stiffeners at the front and the back. In the middle it had a 'D' ring and 2 sail battens sewn in parallel to the back and front on each side of the 'D' ring.
I would hook up the main halyard to the center 'D' ring and hoist it above the boom over the cockpit. The two battens allowed it to tent up nicely in the center. The fore and aft tubes were good spreaders that kept it nice and stiff. Once hung I would just tie down to the lifelines to tension it. It was a good sun shade and even a pretty good rain cover.
I don't have a great picture of it, but you can see part of it in the 2nd picture down on the left in this log book.
http://www.ddunn.org/LogBook18.htm
Steve, I see you have one of the folding seats. We love those. We bought one last year and just picked up a second for this season so we can have dual loungers in the cockpit.