With the right prop and ventilating the pocket, you may not need the Arneson drive and all the mod work for that.
Put a 1-2" vent hole and ball valve for control in the pocket by the shaft log and find a semi-surfacing prop with rake similar to the shaft angle. (Prop Gods or Herring)
The owner would need to be willing to be a guinea pig though.
https://www.boatdesign.net/threads/p...tunnels.19863/