I did Andrew. Lived and died by that book. Bike fit is right on for me.
As far as the subject goes. Used bikes are worth what you can get for them. I always think a no reserve auction on the Ebay is the true test of value for that point in time. Maybe somewhere someday you might get your idea of a fair price, but Ebay is where you get what you get in real time.
My geared TT /Tri bike is a round tube Waterford. (round tube fixed it the TT bike of real men) It was state of the art before aero tubes came in style. And is still a beautiful ride. I still love the bike, but bet I couldn't get 1/10th of what I think it is worth. I just give my old bikes away to people that really need them. I feel better in giving than I would at selling a bike at a huge discount.