Another friend (also owns a PA) and I discussed a larger rudder might help but didn't think about running with 2 rudders. I see how that can be of help. Did you run both rudders to same turning control? who purchased a PA
I ran lines from the quadrant that rotates the OEM rudder to the Twist and Stow, so they both turn the same amount at the same time in the same direction. I don't want to get in a useless urination tournament on this forum. I have done a lot with vehicles in the water. Got paid big bucks to control them. Air vehicles too. Same principles just a different rho for the fluid. Designed the first folding curved deployable fins for a multi mach missile and tested them for flutter in a wind tunnel. Found a non contact way to determine the first seven modes of vibration for those fins and for the wind tunnel models. Tuned the wind tunnel models to prevent divergence in the unsteady flow period as the tunnel transitioned from sonic to supersonic flow.
Don't know too much though.
Hobie PA14 with a mod or twoSome random Modification Pictures