I have just the loop, no nock sets. Some folks put a nock set above the upper knot and below the lower knot to keep the loop from moving, but if it's tied in correctly it won't anyway, so why? I've been shooting a loop w/ no nock sets for about.....2 years now and have never had a problem. You don't need to serve the loop in, either.

I've found that no nocks are better because you can now draw the way the loop is intended, directly behind the nock eliminating pinch. It shouldn't affect your kisser button at all, but it will move your release hand farther back toward your ear a little bit.