You cover a lot of ground in your questions.

Wind generators Blades run at half speed for proper loading, thus when unloaded they spin faster.
Shorter blades spin faster. Higher TSR blades will spin blades faster.
More blades on a turbine will slow down the RPM. 5 blades spin slower than 3 which is slower than 2 which is slower than 1:-) (yep somebody tested (verified) this out couple years ago. Unloaded blades are not making use of the wind, may as will be shorter.

PMA output voltage is proportional to RPM. Once at cut in, higher winds can't spin blades linearly faster. Ex: Cut in is 6MPH at 100RPM, at 12MPH the blades will NOT be spinning at 200RPM. If it does spin at 200RPM then the wind is overpowering the generator, (Assuming 12v battery) which is now outputting 24v, this voltage mismatch has to go some where. The voltage is dissipated in series resistance as heat. This explains why some have discovered with higher winds they can use series resistance for heating without loosing much going into the battery! If no external resistance then the windings in generator are the weak link and fry.

Will stop here, to go further will become long, weather is too nice outside!
Also like Flux said more details are needed.