When I figured out I wanted a sailboat I just used yachtworld and narrowed it down to 2-3 makes. Once I decided the b-40 was the boat for me I started an archive on every b-40 for sale. I keep this up for about six years. During that time a developed a very good idea of prices, price reductions, photos, and how long a specific boat stayed on the market, etc. Of the 200 b-40s made I have a file on about 120 of them. Once I had about 200k burning a hole in my pocket,(!) I think I looked at about 6 boats total in two trips. One trip to Annapolis and the other to Maine. I made an offer to one in Maine which was not accepted. 6 months later I made another offer, slightly more money, and the owner did take it. As far as compromises- each boat is different even within the same make, so it is hard for apples to apples comparison. The previous owner tried to used the dink, outboard, and ships clock, barometer, as bargaining chips. We ended up w/the dink and outboard, but not the Chelsea clock and barometer, which were the real expensive old school ones.
The boat we bought had a complete refit 3 years ago so the new motor, sails, paint, instruments, etc. made this boat more desirable than others we looked at