RE: STS VERTICAL LOCATION
Another factor to consider and measure out is how faryour sts is sticking out into the brace height of the string. Does the bow string at rest touch the sts, does it press against the string tightly or even push it out a little. Sounds like it acting like the bridge of aguitar shortening the string and increasing the speed/ vibration of the of the string. Sort of likea temporary shortening of your axle to axle length right before the arrow is released. Just something else to consider. Interesting. take care..