We are in the process of installating a junior garn. Looking to see what folks have used for the ridge insulation board under the unit. The installation guide says to use 1 1/2 inch foil faced polysocyanurate foam (Thermax or equivalent) rated to 25 psi, 2 lbs density. We are having difficulty finding such a product in our small town. The ridge pink or blue insulation is available and has a high psi rating, but low operating temp. Any suggestions on what to use? Thanks !!