I have two Wallytractors, another one on order, and the Wallyskater. The Wallyskater is the best device that I have seen for getting anti-skate set exactly where you want it. I love my Wallytractors and find them very easy to use. Switching from Baerwald to Lofgren and back is real easy. That may not be useful to other people though. I have also found Wally's "five point' alignment system to allow me to set overhang more accurately than with a standard "2 point" mirror protractor. YMMV.
If you are going to order one of Wally's tools, place the order directly with Wally by calling him. His number is on his website. Tell him what you want and then send him the check. Call him every two weeks to remind him that you still haven't got your item yet. Be persistent. After six or eight phone calls you will get your item. Wally has a wealth of information on analog set up. He usually likes to talk. Be nice to him when you call, and you can learn more than you ever knew existed about analog setup.