The Krentz Modulator is a really excellent product out on the market, which has helped many of our customers overcome and better deal with wolf-tones and tension with their instruments. Highly recommended.
While it can be intimidating for during the first installation, it is a simple device to install (comes with good instructions). When time allows, we will likely make a short video to demonstrate how I install them. But, it really does go a bit faster the first time to have a second pair of hands and ears when installing. One person can play, while the 2nd person is adjusting the location of the device on the viola.