Regarding a backstay adjuster, it certainly helps to be able to twist the sail for that added ounce of speed. Having said that, it really depends on the type of sailing you prefer. If you decide to get one then definitely go hydraulic as I don't think you'll get much us from a manual. Of course if you are going to get a backstay adjuster then the corresponding forestay adjuster comes in handy.
Jack Harris is the owner of "Temptation," a 1985 Tartan 34-2. Jack is a Professor of Sociology and an international consultant to local governments. He sails out of Prinyer's Cove, Picton, Ontario, Canada.