The magnets must alternate on one plate. N up, S up, N up etc. That's why there must be an even number of magnets.
Then the two rotors must be aligned so that they attract. And boy, will they attract! Enough to literally crush your hand, so be careful!
A complete guide... I wish! I am trying to work something out as I go, but its complicated. Start with max theoretical power
P = 0.35 A v^3
Where A is swept area of blades, v speed in m/s, and P power in watts.
Then you need to work with tip speed ratio, and the RPM vs watt graph of your generator (a straight line).
If you figure out a complete guide, let us know!