Power depends on correct air/fuel mixture at all throttle settings. Most carbs are setup with a lean mix at low throttle settings. The design of the PWK carbs makes it almost impossible to fix that. Notice how Honda switched to Mikuni TMX from PWK after 2000 for their MX bikes.
But its nearly impossible to figure out what to do without a jetting calculator because every tuning factor except the main jet overlaps at low throttle settings.
When I had an impossible to correct carb I was inspired to make a jetting calculator and now it is the best available.
I highly recommend everyone read about it at
www.dragonfly75.com/moto/carbjetting.html