Try a search for "heterodyning" for a more "scientific" placement of your noise limiters. I have my reference saved as a word document, and I don't have the tech savvy to attach it, so I will try to copy it here. I do not remember from whom I took it, so I can't give the proper credit, but I know from experience that it works.
HETERODYNING
Most of us have tried various types of string silencers. Some folks have trouble getting any of them to work. Here is the solution, no matter the type of bow or type of silencer material. Measure the distance from where the string leaves the bow limbs top and bottom. Divide that distance by four and also by three. For instance and simplicity let us say your measured length is 60 inches; divided by four equals 15 inches and divided by three equals 20 inches.
Attach your top string silencer 15 inches down from where the string leaves the bow, and attach the bottom silencer 20 inches up from where it leaves the bow. Doing so cancels out the sustaining frequencies that would make a naked string hum or twang when released. The quartering distance (15 inches) cancels out all even multiples of the frequencies and the distance in thirds cancels out all the odd multiples of the frequencies. The end result is a string that resists vibration after the shot and goes thump instead of twang