Earlier I asked about double sided infused plate, which pretty much needs a core for flow, but since I'm building a prepreg oven, id like to know how it can be done this way. Let's say 2mm thick plate, and I want both surfaces looking nice. Can I simply lay the layers of prepreg on a sheet of glass, another sheet of glass on top, and bag the whole thing? If that won't work,  what other methods are there? Sounds like commercially it's done by pressing 2 metal plates together. The parts I would be cutting out of this plate are a maximum of 8 inches wide, so longer skinnier layups are an option. Maybe I could use aluminum tooling plate with reinforcement ribs going across the width. The ribs could be machined with a very slight bow to give the layup plates a slight convex, when bolting together around the outside it should give good pressure in the middle. Would this be an option as well? Curious to hear different methods
 

Single sided is just a technique to allow the material to breathe so air can get out without having to use the manual technique of having fibres of dry glass that act as a breather. Little bit old hat now, modern pre-pregs seem to be able to breathe well enough without either technique.