I am running a CVT as well With a GC190 on it. I also have the Whizzer sheave.
I have been talking with some of the motorized bicycle guys who run these on the custom built board track racers. They run the stock chain drive but are running anywhere from 4:1 to 5:1 drive ratio. It looks like with the 5:1 drive they are topping out at 45 mph
with the governer removed.
I think the 4:1 ratio will net us a better cruising rpm from what I can see.
I am still in the research / gather stages so I have not tested anything.
The good thing though is that pulleys are cheap. You can buy all sizes and try them out.