In G. Fred Asbell's book "Instinctive Shooting" he says this "Personally, I start by bracing my bow as low as I can. Low enough so I am getting bad arrow flight and noise. Then I twist the string up until everything clears up. For me, that is often where I get the best feel and preformance from my bow."
Of course you have to have a spliced string to do this or a long endless loop.
I know my bows shoot best with a low brace height. I would start with a brace height of about 6" from the face of the bow and increase it about a 1/4" at a time until you stop feeling limb vibration after the shot and for me that generaly the sweet spot.
Hope this helps.
DJ