I've used 8 ply for anything that I intend to hang, for several years. I don't cut my own mats, but anytime anyone has cut 8 ply mats for me, with anything but a computer controlled cutter, I've not been pleased with the results. I suggest you look at the Frame Destination web site (I believe that they are an APUG sponsor). They do a great job and I think that their prices are very reasonable. I've dealt with them for several years and highly recommend them (usual disclaimer;just a happy customer).