I use BCY Nock Point tying thread. I tie 7 half hitches, alternating over/under. Tie it pretty snug, finish it by melting the ends of the last half hitch (no need for a square knot).
You can then twist up/down to tune. When I have them in place (one over, one under the arrow) I lock them down with a bead of super glue on the outside edge of each one. I tie each one so the finish knot is away from the arrow.
If you ever need to move it, the glue can be picked away with the tip of a knife.
I have tied a few million of these in the past couple years, and this is what works best for me.