#1
my whammy bar on my strat rattles in the hole in the bridge unless its reallly tight,i'm nervous because on one of my old guitars my bar broke off in the bridge,also how many springs should I have in the back?
#2
the whammy bar is all about preference what ever is comftorable for you
as for the springs i have 3 but 2 works as well
it depends on your string gague