Frankly when I got the solar pool cover I didn't really have a plan to install it. I had only read about them on blogs and greenhouse gardening forums, and it seemed like if you have a greenhouse in Zone 6 or further north, you had better get one. So I did.
To make a long story short I ended up just making storm windows from the pool cover- easily removable and installable panels for the roof (see photo above). I installed the bubbles facing out (with the pool cover installed on the inside of the greenhouse). I purchased a diamond clear 12 mil pool cover, essentially really heavy duty bubble wrap. I chose the 12 mil for a good balance between light transmission and insulation (negative relationship there, unfortunately). As far as I can tell the R value of this cover is about 3 (regular bubble wrap R value is around 1/ inch of thickness). I like this storm window design so much I think I'm going to make frames and install the shade cloth this summer the same way, rather than on the outside like I did last summer- it is really nice and easy to install and looks tidy.
All the plants are growing well in the greenhouse, and already we have planted a second and third round of salad greens, and radishes. Also, a new item for the greenhouse is cat grass for our burgeoning population of elderly, slightly defective, used, house cats. Although our newest cat, June (see below, and yes this is a cat, and yes that is a real picture), likes to lick cardboard, I thought I could grow her something more enjoyable to chew. Perhaps next week we will have fresh salad greens and so will our cats.