If you want one that lets in light, fits like a glove and are a handy person why don't you just make your own? I made mine out of two different sizes of aluminum angle, two sheets of clear lexan and a small foam gasket along with some pop rivets. I have been completely satisfied with its performance and durability. It lets in so much light, I changed the screen cover to a sun screen material to cut down on the glare. I can see the stars at night and watch the rain clouds build up during the day.
Here's a cross-section and how I did the corners.
4CU 2699 / AIR 10 / TAC AZ-1
I'm haunted by aluminum.
Charter Member of the 4 Corners Unit.