Hi Rob,
If you would add a bowthruster it would be best to use something like a pump with in- and outlets in the bottom of the hull, as you can then not see them anymore.
Isn't steering with the props (1 side forwards the other side backwards) in combination with some helping tugs enough?
The length-to-beam ratio is very important to get a good manouvreability, a length-to-beam ratio of 2 means very manouvreable, and 8,2 (for Hood) means very course-steady and not manouvreable.
You will really need a large rudder and 2 ESC's to steer with the props.
Greetings Josse