flash.....the speed balls do work, however the trick is getting them in the correct place on the string. You really need to shoot arrows through a chrono, move the balls, shoot more arrows and repeat. Eventually you will find a "sweet spot" that gives you the most speed increase.

As for using a brass nockset in place of the speed balls......DON'T! The brass nocks are not designed for the stress axially along the string that you find at the ends of the limbs near the cams. They are designed for the perpendicuar stress you get at the center of the string. Essentially what can and will happen is one or more of these puppies will come off on the shot, possibly causing some severe damage to yourself or bystanders. If you do use brass nocks, relax your string, and slide some heat strink tubing over the string and nocks, then shrink it. This will keep the nocks in place if one happens to "liberate" itself from your string.