The 4 mil. Saran wrap is thin and wrinkles, which will leave wrinkles in the epoxy. Wax paper can leave wax, which will prevent subsequent layers from bonding.

Laszlo

Put the 4 mil on top of your workspace, between the sets of panels, and on top of the top panel set and under the weights or clamp pads you'll be using.  Also, stick packing tape along all scarf joint edges (that will be four pieces of tape for each joint) to reduce clean up of epoxy squeeze-out after the epoxy cures.  The excess epoxy that squeezes onto the packing tape can be peeled off.  Without the tape the excess epoxy would have to be scraped or sanded off.  The tape might seem like a pain but it's minor compared to removing epoxy lumps without damaging the panels (assuming you're going for a varnish finish).

Yes, as Laszlo says, the saran wrap will wrinkle. Try stretching it out and holding it in place with masking tape on each corner.

Robert