There are some other strange issues that can come up when using some steering modes. mode 3 causes the rudder to work against the motors in reverse since right on the the motor control is always clockwise rotation but the rudder changes its direction of rotation depending on if its going forwards or backwards.
The way i was going to solve the problem of mixing different control types was having a different tune for each and then change the parameters with lua when i change control type.
so when cruising my boat will have both motors set to throttle with rudder so no skid steering so it can continue even with a motor failure and it wont try and steer the boat with the motors when sailing. but when I set the switch to mode 2 it will change the motors to left throttle and right throttle, disable the rudder and change the tune to match the new turn rates, then mode 3 will be my thrusters with main motors disabled. essentially letting me switch between skid-steering and ackerman and omni motors on the fly.