Ahoy Danny,
You have been given some misinformation concerning the Staysail. You can not get 1/2 knot more boat speed by getting rid of the Staysail boom. If you re-sheet perfectly using the existing sail without the boom you will gain nothing when close-hauled, and you will lose performance when reaching or trying to run. If you eliminate the boom and get a new reshaped Staysail you could possibly get .1k when closed-hauled but you will still lose when reaching or trying to run. There are a number of reasons, to eliminate the Staysail boom. Sailing performance is not one of them. The biggest effect on performance concerning the Staysail is to not use it. Just recently, Gary Burton and I were out on Elizabeth Ann and trimmed to a close-haul to the best of our ability with the Main, Staysail and Yankee. We then dropped the Staysail and lost .75k. We re-set it and recovered our .75k.
About the windvanes: All of the servo pendulum windvanes will work equally well on the Westsail-32. (I haved used just about every production Windvane made for at least one long haul delivery). With long term use, all of them have their short comings. All of them their strengths. If you're looking for one, keep your eye open for a Fleming also.
Good luck, and let us know what you do, Dave