Axial Flux generators

I am building a 10kw(approx) axial flux generator to be driven by a wind turbine. The rpm hopefully ,will be around 150 to 200. I have been advised on several ways to construct the rotors and stator. After listening to all the advice I think I will rule out circular magnets and coils. I believe that oblong or rectangular coils and magnets are more efficient. Has anybody out there done any designs on Cad using these shapes or even trapezoidal shapes.

I was wondering how long(length of rectangle) could the magnets and coils be before they would be impractical or inefficient. How would I know how many magnets and coils to put on a disc. (what I mean is how close could they be to each other without effecting each other). Is there a ratio between the amount of magnets (or the total strength of the magnets) and the thickness of the steel backing disc(for magnetic saturation).

If anyone has cad dwgs of designs I would appreciate a look at them please. My email address is michael@roof2000.com. If someone is sending some dwgs could they send them in Acad 2000 version please.