Any Radon Mitigation Guys Here?

[Porsche-O-Phile]

If so, I've got a question regarding sizing a basement under-slab depressurization system; I'd like to ensure proper evacuation and can't seem to find good resources online regarding fan sizing and required number of slab penetrations (e.g. a fan pulling "X" CFM at "Y" inches of static pressure will cover "Z" sq. ft. in such-and-such a soil condition, which should give a drop of however many pCi/L...).

I'm planning starting with one penetration located more-or-less centrally, monitoring the levels for a while (1-2 months) and then adding more fans/pipes as necessary, but I'd think there is (or should be) a formula to do this a little more quantitatively than this sort of "wing it", trial-and-error approach based on variables such as:

1. Permeability of under-slab soil (estimated or known)
2. Size of floor plate (obviously)
3. Current pCi/L level (target is <4.0 max, <2.0 desired)

Let me know - I want to start work on this in the next few days; other basement work is nearing completion. TIA.