do you have the a/c idler pulley, or has the belt been re-routed already? I had to use a 5 rib for my temporary ps delete/bypass. It was all I could find, did the job though.
I dont have a AC delete like yours but a gates belt tells you what length it is in the part number. A K080390 (10% supercharger belt) is 39" long. A K080395 would be 39.5" long. Take a piece of string and route over the pulleys just like the belt would run and than measure it.