Danny,
Here is a picture of the home made fridge incubator that I built for this last seasons clutches. I think it came out great. It is a little biger that the one you are attempting, but if you have any questions let ma know, as it is the same principles as yours. I had 11 clutches in there this year, but I feel that I can fit about twenty in there at one time if I have to. Let me know if you have any questions. I need to get some better pics, but if you want to see anything specific, let me know, and I'll try to get the pics for you.
Hope this helps,