do you want to advance the timing? Try finding the high altitude CPS.
If you really really want adjustable timing you're probably better off doing it at the distributor, because getting under the Jeep and messing with the CPS is a PITA, and not likely to be terribly repeatable given that you really can't see what's going on up there when you install it. Unless you pull the drivetrain to change the timing.
it's not going to increase the horsepower unless it's coupled with more fuel/air/compression in some fashion.