"He who marches out of step hears another drum." ~ Ken Kesey
I've spoken to Roger Jennings himself (a few years ago) and he uses cardboard tapped to the frame.BTW, I have all Jennings equipment.
Thanks for the info I have decided to put the Jennings press up for sale and i bought a 6/4 workhorse mach.
Wouldnt you just set the off contact once? with the plexiglass? Only take prob 2 minutes.The plexiglass does shirts and when you go to sweatshirts i taped a paint stick on the screen and viola, off contact for fleece.
It may not be the "right" way, but I have a Hopkins Pro-Line 6/4 and I just tape some spacers under the outer edge of the screen frames. You could use 1/8" Plexiglass or equivalent acrylic sheeting under BOTH ends of your screen frames to keep them nominally parallel to the platen. I don't usually use anything under the back ends. Paint stirring sticks are about right, and I've used them too.