I need advice for a flat roof that I re-framed to put 8" of pitch over 19ft into. I've been told that a single ply (base sheet, granulated cap) Dibiten system is better and last as long or longer than a 2 ply APP torch system (base sheet, smooth, granulated cap). I know that Dibiten is ALSO a torch down system! In my opinion, I would rather spend a little extra money and over kill it , rather than under kill and go with mininums. I live in Southern California, so ice and snow are NOT a problem!!!! But I do not want to mess with this roof for at least 20 -30 yrs!!! Please. NO advice to go with a BUR (hot mop), PVC, or self sealing type system, I don't think thats going to work for me. So what do the experts think??? Oh, what is the best base for this?? I've been told 25lb, 40lb, 75lb and lay fast or similar type under layment of an SBS type nature. Most guys in my area are going with 25lb. I appreciate all opinions and advice!!