Ray,
Couple of things you can try. I have taken the pulley off of an old Schwinn bottle generator and dribbled a bit of sewing machine oil down the shaft and it seemed to help a bit. Some tires like Schwalbe and some Kendas have a raised ridge on the side of the tire just below the tread, it is called a generator track and is intended as a place for the generator to run. They make little rubber covers for the generator wheels that will help keep wear down as well as reduce slipping in wet weather, however I cannot find a current source for them.
I would use stranded wire rather than a single solid conductor. FWIW I cut up old cellphone chargers to get wires for my generator equipped bikes. It is the right size, and is usually color coded.
Aaron
