Well I found a local source of some very cheap Mylar... So here is my first upgrade to my plant shelf. This has to be 1mil thickness (or less) it's pretty difficult to work with, and the section that went up in the back I actually crumpled up as scrap. The original plan was to use wooden sheets to give a stiff backing for the mylar, but it's Sunday, cold out, impatient and tired so I just wanted to see how the scrap peice looked.
So far I'm happy with how it looks and want to see how the plants react to the upgrade.
A comparison between my two sets of lights, one with a Mylar reflection on the back, the other just the fixture. I really couldn't see a visible difference. But there is a heat difference on the shelf now.
Remember this is just my quick fix to see how the light difference would be, I might tidy this up later.
Next step, add sliding glass doors to the shelf so can let the Nepenthes have some room to grow!