Oh, wait. A Platform Mount requires covering the edges. Do you mean to hinge it to a slightly-undersized backing board, and then attach that to the background? That would be a good idea.
MurrayBoy, are your gummed linen hinges failing on the art paper? If so, I suggest using a bit more moisture, then allowing the adhesive to rest for half-a-minute-or-so before applying it to the paper. Personally, I would be using methyl cellulose paste or freshly-cooked starch paste for this, and hand-torn Japanese paper hinges.