Bicster,
I just got my new 54" Black Widow KB, 53lbs @28" shooting about 550 grain arrows and it is absolutely quiet & dead in the hand... Using the stock Fast Flight string, one set of the stock spider silencers @ 9" from the loop/string intersection ends and one set of woolie whispers @ 14" from loop/string intersection. Bow could not be smoother, quieter, or less vibration.... I'm sorry to hear yours was finicky, but thought my setup might help others as well... I just used the recommendations that came in the owners manual for the spacing and figured the spiders & the woolie whispers might attack different frequencies.... My post is intended to be helpful, not divisive. I know every bow is a little different... :-)
KAZ