Thickness of parabolic reflector


Some time ago I asked about the size of perforated material for use as a parabolic reflector material and I got the reply of  wavelength/10 now I ask about the thickness,
I have been told it doesn't really matter and have even suggested I could use space blanket. i was looking at 2mm thick aluminium slotted into the guides of the paraclipse Dish i now have to build up. Also looking for a recommendation of calibration of remote AZ/EL sensors. I need them to be accurate enough for 2.3Ghz EME (possibly later 10Ghz)

looking forward to replies - direct if you please