How quickly should oil pressure come up?

@Mattax I knew that was the case I was just making the point that oil viscosity isn't as simple as some suggest. Thanks for the graphs that's great info. I was running the 5W back in CO for the sub-freezing (and sometimes sub-zero) cold starts but where I live now that's not much of a concern. It barely gets below freezing here in the coldest parts of the winter, plus I park my Duster in my attached garage.