That advice (1/2 the reading) is too general. The power valve choice should be based on a figure slightly below your highest cruising vacuum. A high number will open every time you touch the gas and kill your mileage, a low number will give a flat spot on acceleration.
Important: the PV number has nothing to do with jetting, it's not how much fuel is added. This is entire controlled by the power valve restrictor channel, which is 2 holes drilled in the carburetor body inside the flat bowls. The main jet only controls cruising mixture, all enrichment is added by the PVCR. The different 390 models have different PVCR, and will have very different full throttle mixture with the same main jet.
4160 is list number
What is the list number?
