We use Vista sign system a lot. A university customer is having issues with the inserts wrinkling under the lenses after a month or two, presumably due to humidity. We are using HP Photo Professional paper, 9 mil, printing on a 360 HP latex printer. Any suggestions for a substrate that doesn't wrinkle and can be printed on the HP 360? We bought 12 mil paper, Briteline, but it retains the curve of the core and we have print head strikes. I contacted Vista directly and their only suggestion was to apply vinyl to the outside of the lens, which is pointless as it still would require some sort of paper behind the lens. We used to use Optima OptiSolve 9 mil paper with no problem but that company is apparently out of business.