When I was doing partial mash I settled on using about a gallon of water to mash. Something to consider, it always seemed to me like it was really easy to over sparge doing a partial mash. 4.5 quarts sounds about right to me, but keep a close eye on it. If you see clear water coming out of your grain bed, STOP your extracting tannins, and I've had to drink my own over sparged beer, yuck!
I have the same book and have brewed many recipes out of it, enjoy and good luck!!