How big is your crew and how much experience does the crew have? Also, if you will be sailing alone more than two up, check the weight of the boat you are buying, as you will be moving it and stepping the mast alone too. Lighter is better, obviously.

I recomend a spinnaker cat of some type. All the F's have them. F16, F17, F18 two up and I20.Sailing downwind solo on a fast spinnaker cat in a 20 knot blow is about the most demanding sailing you can do. Expect to go swimming a few times until you figure it out.