I have always started with a string about 3/4 to 1″ too long, and try shooting the bow, and twisting the string to find where the bow seems the quietest, shoots the smoothest and still does not slap your hand with every shot.
I prefer a lower brace height than most, because it makes for a quieter shot, and a lower brace height will add a little to arrow speed, due to the slightly longer power stroke.