After much nashing of the teeth and help from others on this forum, here are the settings I've found to be the best at the moment when using a Motorola Bionic Lapdock which has a native screen resolution of 1366 * 768 (11.5").
Set monitor to HansG 171D
Set colours to 16M
Set Resolution to 1280 * 720
Text is still a little too small for my liking, but is quite usable and much better than the default 1920. I suspect any monitor choice that allows a 1280 * 720 would work.