Mylar does have a transparent backing to it and is very fragile to use in that manor. The panda is perfect for what you are doing. Black on the outside and white on the inside is the way to go. There is a new book coming out by the end of the year with several diagrams and plans to build grow rooms with PVC and other common elements.

Very nice job OR FREEBIRD!

This link is for you and anyone who want to use PVC pipe and panda plastic

http://www.snapclamp.com/prices.htm