Question:  UV Light Boxes for Photopolymer Resists

I have a question on light boxes for processing photopolymer resists. All of the instructions, discussions Ive read for this process show a UV light source shining down, but traditional UV exposure boxes (as used in screen printing) shine the light up. For the purpose ofapplying resist to metal, does it matter if the light shines up or down? Is one easier to work with? I am considering the following two options as a quicker/easier exposure method than building one myself. Id love your thoughts/input!

UV-box-Ebay Technology-Etrade on Ebay: 10.2″ X 8.3″ Vacuum UV Exposure Unit Hot Stamping Screen Printing Curing Plate 

Eco-Exposure-Light  Eco Exposure Light from Crafty Printers


I cannot think of a reason why the direction of the light would matter. You would just place the side with the black image, face-down onto the light instead of turning it up to the light.  It would probably expose a lot quicker so, you’d have to make some test pieces.

 The one on ebay looks great and is a good price.  I haven’t done any etching in a long time but, from what I remember, I made a sandwich of the metal, the film, glass and a backing, then clamped it together.  My question on that box is:  will there be enough room to fit this “sandwich” between the glass and the top?  Maybe, and especially, if there is a tight fit between the glass and the top, you don’t need the “sandwich”.  The glass and the backing are there to keep the image fitting tightly to the metal.  I wonder if you could do away with the “sandwich”  but, I also wonder if there is enough room to fit in various gauges of metal.  I’d ask them about the space between the glass and the underside of the top.
The Eco Exposure Light looks like it should work too.