Thanks Brian, all this advice helps immensely when it comes to a new build.
I will be fitting lights to the tug most definitely, along with a working winch and various other small features.
I am going to trial MMM's T12 motors first, running 70mm korts. I have seen some folk fitting schottel drives to the Portgarth but I personally favour steerable korts for this tug, and a bow thruster, which I haven't decided on yet.