It sounds like an interesting problem. There is not a one button solution to get what you want, but maybe I can describe how I would attack this problem—and Rob’s comments below are always excellent recommendations.

Usually in fluid dynamics we talk about the pressure drop. We use the pressure at various points or cross-sections of the flow to determine what is the drop between them. Since this is a laminar solution, I will assume there is a linear relationship between velocity and pressure drop. This is where the idea of flow resistance comes into play as it is analogous to an electrical circuit.

You could then find what the resistance for each component (a hole, or a section of pipe) and then make an equivalent electrical circuit. Then you could make approximations for the other simulations and then conduction the simulation to see how close your prediction was.

In the electrical circuit analogy, the volumetric flow rate (Q) is the current (I) and the pressure drop (dP) is the voltage drop (dV). Thus, to determine the resistance, we need the pressure on either side of the component and the flow rate (R = dP /Q). This is where Rob’s idea with the named locations comes into play. You may also be able to create such surfaces in post-processing.

I am old enough to remember ’84. 35-5 was quite remarkable and will likely never be topped.