Unfortunately, I'm on a student's budget (cheap!) so I won't have the luxury of buying a Nova, nor do I have the luxury of space to use a set of trays. So...
I don't intend to stop them sticking. I'm actually intending for them to stick. As I'm using RC, the chemistry does not soak into the base, but just reacts with the emulsion surface. So as long as the base-side sticks to a panel, there is no problem. If one side is stuck, then naturally the other side should not be.
If I need to get a non-stick surface, Ken's point about the lighting panels for flourescent lights should do the trick.
I will build a prototype with vertical walls first, rather than slanted walls, to see if it works well for me. I might build one with slanted walls at a later stage should I need a bigger processor.
I did the calculations, a slot that is sized 300x250x15mm should hold 1 liter of chemistry comfortably, with a little room at the top.
Sorry to bring this thread back after over a year.