Well I finally got the right set-up on my Vintage 57 Strat after much trial and tribulation.. just thought I would mention something about tuning stability which I noticed drung adjusting the string heights at the tremelo particulary on the b/e treble side.
I had a problem at times during setting up where the B string was a real B*****r to get tuning stability on and one thing I found was that the tension in the strings had to be right to get the right balance and tuning stability ... just a 1/4 of a turn on one of the adjacent strings made all the difference. It was the only thing I changed that made a difference to the tuning problem so it's worthwhile mentioning it as a suspect place to look if your strat has a problem wiht strings going out of tune often.
HTH