I have a similar set up to Smaug.
http://www.talkmorgan.com/ubbthreads.php/topics/220810/6
The ball mount goes through the hole already in the dash. I have a waterproof case similar to this. You can still use the touch screen but not hear the audio. For audio you would need a Zumo for a bike & a bluetooth ear piece.
https://www.amazon.co.uk/d/e46/ChargerCi...of+sat+nav+case