Suggestions for thermal buffer for MH canopy

[stilmas]

Hello,
I'm looking for suggestions on what material to line the inside top of a DIY light fixture I built to mount 2-PFO minipendants in. I was thinking of using some roof flashing or sheet metal then use aluminum spacers to hold the pendants from touching the metal surface. I need suggestions of what I should use. Thanks!

 

[DK]

Are there fans in the pendents? I am not sure why you would put them in another "fixture"......wouldn't you just attach them to a rack or something like that?