The reversible method you're looking for is the "static mount". Use a piece of 1/4" acrylic as the mount board. Trace the shape of your print on the paper masking, and trim it away where the print will be located. Leave the mask around the perimeter of the print, so it has the effect of a "sink" mount.
Generally, I reinforce this kind of mount with hinges, as static changes with ambient conditions. The print could fall at a time when static charge is reduced.
Are you saying the artist wants to sign in the white margin of the print? I suggest you talk him/her out of that, or urge reprinting with a wider margin of white at the bottom.
Do not allow the artist to believe that 1/16" is adequate overlap of the mat. The print will expand/contract and creep within the frame more than that. Being a bit blunt, I would absolutely, positively guarantee your artist that one or more edges of the print will pop out of the mat opening, eventually.
You know more about framing than the artist does. Don't let him/her tell you how to do your job. Instead, make sure he/she understands the problems -- become the consultant.