I just tie mine around the string and pull the knot very tight. They will generally stay in place and you can slide them around to find the sweet spot. As far as length goes, ONE INCH is all you need (has anyone else ever used that line?). Seriously though, if you trim the whiskers to one inch on either side they barely slow the bow down and do a wonderful job of quieting string noise. The great part is that they are cheap and will last as long as your string. Oh yes, one little trick for putting on the whiskers. After you put them on but before you cut them, measure and draw a line across the whisker with a marker at one inch. Now pull (stretch) the whisker and cut where your marker line is with a scissors. This will help to separate the whiskers and it will snap back to the one inch length.