I processed my first roll of film on Monday night. I thought I had done a great job, but when a pro looked at the negatives she said they were over processed. It was processed in D-76 at the 12 min. recommendation per Kodak. I agitated as per Kodak, the first 30 seconds and 5 sec. every 30 sec. I am about to process my second roll. It is HP5 shot @ ISO 400. I will be processing it in D-76 again, in a 2 roll tank. My question is how long should this stay in the D-76? What about agitation?