Porosity settings for an AC coil

[tlewis3348]

I'm attempting to account for flow through the AC coil for a commercial chiller in a simulation where the unit is sitting in a wind tunnel (the goal being to make sure the system survives a hurricane). I want to accomplish this by approximating the coils as porous volumes. Assuming that I know the pressure drop, the face velocity, and flow rate of the air going through the coil, how would I go about determining the settings to enter into the form shown below?

If I need to know additional characteristics of the flow through the coil, what would those be?

Additionally, do I need to define a custom material (i.e. use something other than "Glass Wool") to use in the "Solid Definitions..." section shown below?