Tiny Wind Power - Next Step

Re the cogging (stepper detent torque) that was why I suggested multi blades. With a stepper you dont need high rpm like most mills, you need a high torque low rpm turbine.

Re the blades backwards, the face of the blade (facing the wind) and the leading edge should be flat, the trailing edge of the blades goes "back" which puts its drag in the rear of the blade movement and the rear of the wind direction (ie low pressure zone).

Mr RB said:

Re the blades backwards, the face of the blade (facing the wind) and the leading edge should be flat, the trailing edge of the blades goes "back" which puts its drag in the rear of the blade movement and the rear of the wind direction (ie low pressure zone).

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What you say makes sense, but seems to differ from these folks:
Photos of PVC Wind Turbine Blades - Wind

Making PVC Wind Turbine Blades

That way needs less clearance, most of those pictures show little clearance between the hub and the generator housing. There's probably not that much difference in the efficiency on small turbines anyway.