Digital BW, The Print

I print with Ultrachrome inks on Epson Premium Semi-Matte paper which  
is then laminated. I want to mount these 24x36 inch (60x90cm) prints  
on aluminum sheets for an eventual exhibition. What thickness should  
the aluminum sheets be (1mm, 1.5mm, 2mm)?

Obviously, thicker sheets will flex less but I figure that, if the  
prints mounted the aluminum sheets are then hung on a gallery wall  
(using double-sided adhesive tape?), flexing should not be a problem  
-- so that I should be able to use 1mm aluminum sheets. Is that right?

I like the idea of selling prints mounted this way because the buyer  
can then frame them any way he or she desires -- the prints have a  
1/2 inch white border and, as they are laminated, can be framed  
without glass.

--Mitch/Bangkok