Any chance you could provide a little more detail?
Does "redoing the head" mean replacing the toilet, redoing the whole system...or just redecorating the room?
Seriously..."I'm redoing my head including hoses" is a pretty broad statement. I'll be glad to help you sort out how to do it, but I need to know exactly what it is you want to do.
However, I can already tell you that if you're gonna keep the boat on the Chesapeake, there's no point in installing a diverter valve anywhere in the system..'cuz you won't be able to use it. It's illegal to flush a toilet or dump a tank in the Bay. You'd have to be in open ocean at least 3 miles from the nearest point on the whole US coastline.
Otoh, I agree with your choice of hose.
That's about all the advise I can offer without knowing more about what you plan to include in your project.