I used to coat screens before leaving for the day....coat, turn off lights, close door, leave. Then in the morning when they were dried I'd lean them up against the wall in a dark closet until we needed them.
My exposure unit is on a cheap IKEA table with cheaper legs. Wrapped 3 sides of the table in 100% light safe black heavy duty contractor bags (cut open into big rectanlges and duct taped to the table top). The back side is up against the wall. Underneath is enough room for 16 23x31 screens to dry horizontally with alphabet blocks between each screen. We got smarty pants and put two sets of wood 2x4s with dowels in them running vertically in the back, nailed into the wall, so that I only have to put blocks on the front sides of my screens.