I'm not a PassPort/Visa or Futaba expert, but I'll relay some of my experience that might help some others.

Apparently the base or default mixing types of options are different between the 12X and Futaba. With the 12X, the split rudder function allows both rudders to move together, and both to split outwards for an airbrake effect. The PassPort / Visa use a different type of split rudder function where in "normal" flying mode one rudder stays straight while the other moves (ie, when using right rudder, only the right rudder moves and the left rudder stays centered). I found this to be super smooth for normal flying, and a nice feature, but I was not able to get this mode on my 12X without using Pmixes.

After I had flown my PassPort a bit, and talked to Chip about the mixing I needed (that he wasn't finding a need for), a couple things were figured out -
- the dihedral angle on the PassPort was not ideal on the earlier models, and it was corrected on later models and on the Visa. I doubt my plane would have needed any rud>ail mix with the updated dihedral angle.

- Chip had a small amount of rud>ele mixing on his PassPort (which I think has been eliminated to zero on the Visa), and mine needed a lot more. The differences came down to a couple things -
1. Chip was using a curve mix, and I was using a linear mix. With the curve mix, Chip had 1-2% mix starting just off stick center and it stayed at 1-2% mix all the way to full throw. Using a linear mix (like I did initially), I needed more than 10%, and in some places it was not enough, and in others it was too much.
2. I prefer to have the plane setup such that it will spin with rudder/elevator only....no aileron....and this meant I had to move the CG further aft than where Chip was flying (which is where he had "tuned" the design for minimal mix).

I flew my PassPort with split rudder, and with the rudders moving in unison. The mix required in each mode was slightly different, and to recall, Chip was/is using the same mix for both modes. I couldn't see any reason why the mix in each mode should have been different on my plane, but it was. I did get to the point at which my PassPort had <5% mix in all modes, and exhibited no strange rudder coupling in the air, but it took a lot of work with fine tuning of mixes. My rudder Pmixes were not linked to the throttle in any way, and were not tied to any stick conditions. It is important to keep subtrim and trim to a minimum to avoid any undesired interactions when using multiple mixes (which are needed to get the desired split rudder mode with the 12X).

Regards,