If you want to create a bit of downward pressure on the arrow (which is a great thing), then simply slide your bottom leg of your D-loop down 1/8" and clamp a brass nock point indicator onto the string as a spacer between the nock and bottom leg of the D-loop. This puts the arrow at the top of the V made by the string as it's at full draw and consequently puts a bit of downward pressure on the arrow. The arrow still stays in the same place in relation to the rest, so the tuning generally isn't thrown off. This should force the arrow to stay on the rest better as you draw.
