I have Avons front and rear now. The bike had only 6000 miles when I bought it so these tires are pretty new. I'm not impressed. My dealer recommends Excedra Max for the rear. I like Metzler Marathon 880's for handling, the newer the better. They're pretty soft. Metzler has a Marathon 888, which seems to be an improvement, though not in our size yet. I'd like to try them.
Don't know of anyone that has reduced their rear tire cross section with anything other than a car tire... not sure that a smaller cross section on our rear (240) wheel would be safe or effective?