Ian do you really want to fit one these
Joking aside I can see the benefit particularly to know what is your most economic cruising speed.
David's set up is very impressive and links through his Raymarine plotter and takes the information from an interface from his engine through some Volvo jiggery pokery. Kiki's Yanmar is not ECU controlled and therefore I could not do the same, I think this could be the same issue for you
I looked at fitting something like flow scan but the cost v's the real benefit to me made me shelve for the time being, other stuff more important has priority.
I 'm sure David will be along shortly.................................