I will be moving up to 8x10 in a month or so when I get my new old Dorff reassembled. A few 8x10 holders I purchased had two sided tape in them. My understanding is this is to keep the sheet from sagging. With 4x5 and 5x7 this is not an issue. How many of you 8x10 shooters use two sided tape? I suspect there are many who do not use tape. Is it considered necessary or just a good thing to do or does not really make a difference? For those that do not tape have you ever had any film flatness issues?