Which Pulley Set Up?

Tuners often put smaller diameter "under-drive" pulleys on the crank (or over-size on components) so they give less parasitic loss, so might be preferable for you. Guys here determined that AC cars had a different diameter water pump pulley than non-AC cars and that is the true reason why w.p.'s have 6-blade impellors on AC cars and 8-blade on non-AC cars. I don't know which is the smaller pulley.