Almost Ready for Aluminum Skin...

Walls are up, spars are in, interior luan is almost finished. Ready to install the fantastic vent that arrived today...
So does the aluminum go directly over the ceiling insulation, or is it better to put a strip of luan over the insulation, and the aluminum over the luan?

So does the aluminum go directly over the ceiling insulation, or is it better to put a strip of luan over the insulation, and the aluminum over the luan?
