1) Take your OG reading
2) Look at the digits to the right of the decimal (e.g., 1.056 --> 56)
3) Divide by 2 (e.g., 56 / 2 = 28)
4) Put a 1.0 in the front and start the D rest there IF needed or desired (e.g., 1.028)
5) IF you actually detect diacetyl in the aroma or flavor, let it rest longer...