As Matt said its takes a bit of trial and error to find the best mast rake to create just the right amount of weather helm to create lift without too much helm pressure..
lack of power in the rig is more likely the fullness or lack of in the sail, this can be a combination of draft and mast rotation /spreader alignment. cat rigs tend to have softer diamond tension and can use more rotation to flatten the sail without using downhaul that would move the draft forward and open the leech so I think that the problem my be in the sail setup....

gordon