The only way that I use D-76 diluted is 1:1. If I use D-76 1:1, I mix 250 ml D-76 stock to 250 ml water for one 36 exposure roll of film and use this as a one shot. The 250ml of stock is the minimum amount to use and get consistent results.
I beg to differ. If you look on the bottom of a Paterson tank it states 295ml for one 35mm film. 500ml is for 120 and Matt mentions using a litre?