Perhaps you're over-thinking this? Other than being unmanageable and expensive, the contraption that you've suggested will undoubtedly crimp the print. Do yourself a favor and scroll - you don't even need to mail order a pool toy! If you already have the material, why not cut an 11" x 40" strip of the width of your roll, set up 11x14 inch trays and give it go with a test strip? You'll get the hang of it in five minutes after which these strange contraptions and extraneous bits of useless hardware will lose their magic bullet aura and suddenly appear as they really are - strange contraptions and extraneous bits of useless hardware.