Tomo, you're right. If you try to put the vinyl behind the lexan, the adhesive will show. Have your vinyl dry-mounted to 1/4" foam core board and clip the board to your stand with office supply binder clips. You may want to remove one of the clip handles, the front facing one, and use enough clips, evenly spaced, to keep the foam core board secure. Or Dry mount your vinyl to 1/8" masonite or sealed stain-grade 1/8" plywood and through-bolt the panel to the lexan with evenly spaced cap screws or black anodized hex bolts or some other fancy hardware you can think of. If you use screws, make sure that all the screw slots align perpendicular to the lexan edge. With hex bolts, the alignment is less noticable.