Try the following.
Enter the menu and navigate to DR EXP (menu page 3)
The first setting is the channel setting and should be on channel 1 which is the one you want if your rudder is on the right hand stick.
Just below that setting it shows the switch position (SW:UP or SW:DOWN) This applies to switch D on the top right of the TX and depends which way it is switched. Move the switch to the desired position where you want the exponential to be on.
When that's done use the Jog key to move the selector down to EXP. You will then notice if you move the rudder stick each way it switches between the two EXP settings.
Hold the rudder stick to the full left position and press the + button and set it to about -50%, then hold the rudder stick to the full right position and press the + button to set the other side to -50%. You will see by doing this you change the curve and flatten it out in the middle which reduces the sensitivity around the center point and means you have to push the stick further for less movement.
Once done, if you put switch D in the other position it turns off the Expo. You can mess around with the curve and where you want to start it etc.
If you want that to work on a different switch, use the jog key and navigate down to the bottom so SW - SWD is highlighted and with the + and - buttons you can change the switch.
Thanks for your advice guys.
Raced today wit the recommended elastic to keep the topping lift taught and it worked a treat. Only problem was I found when I arrived home that the vertical axis pin on my Gooseneck had come out. No wonder the boat wasn't sailing fast.