OHarcher has described things well. I would like to add (and some will argue this, but it is true) that you cannot properly execute the shot with your BACK muscles if you turn the release to vertical. I recommend staying somewhere between horizontal (or flat, as OH said) and 45°. This will allow you to use yout Rhomboids to set the release off.

I have also found that I seem to get the most consistent release by only using 2 fingers. This is a very personal thing though, but for me, I seem to tense up a bit more with 3 or 4 fingers invloved.