I am going to process my first roll of Kodak Tmax 100, 35mm today. I am using a 2 reel plastic tank. D-76 developer, 1:1, 12 min. Kodak indicator stop bath, 1:63, 30 seconds Kodak powdered fixer Wash 5 min. Kodak Photo Flo for the final rinse. 30 sec. Everything is being done at 68 deg. F. My question is how long should I fix? The Kodak site says 5-10 min.???