6ft PVC - wow, that seems long! How thick is the wall? It would be great if you posted a few photos of the process of cutting them out and smoothing them. You could get nearly ten times the power compared to the 2ft blades, so be careful!
Flat blades... are your blades flat, or curved (from a PVC pipe)? Angle I would guess around 6 degrees, assuming a three bladed design. You want to optimise for the tip, where most of the power comes from. I would understand more if I saw a photo...
Magnets NSNS.... yes, so that rotors attract. Note that 24 powerful magnets attracting each other will quite happily crush all the bones in your hand.
AC will not be square, unless design is poor it will be a sine wave, full wave rectified. The three phases combine to form a DC current with a ripple. The battery is basically a big (and slow) capacitor, so I can't see the point of adding a cap.