Two thoughts for handle grip. First, you're on the right track with the hairspray for bicycle grips idea but you need to take it one step further. Bikers have been using cork impregnated tape for almost a century to wrap their handlebars as it absorbs moisture, grips wonderfully, and dampens vibration. You can get it at any bike store and it is usually self adhesing. Same thing with tennis raquet grip, if there isn't a bike store handy.
Second, you can get 3/16" aquarium tubing and wrap the handle tightly with it. This is basically the same effect as the Jameson and Kelton handles. Once again, damps vibration well.
Dietrich