I've just read a quote from Eddie Van Halen about doing setup for Fender Strats:
"Setting up a stock Fender vibrato tailpiece to keep it from going out of tune is as painstaking a process as setting up a floating Steinberger TransTrem. You have to wind the strings a certain way, and the nut has to be cut differently"
This came as a surprise for me. I've never seen a Strat nut being cut differently than a Telecaster's, and I always wind strings the same way in all electrics no matter if they have string trees, fixed bridges, or whatever. Am I missing something?
There's an italian luthier Frudua who has a very comprehensive seies of youtube videos covering optimizing fender strat temelo setup and modification.
Whilst a lot of what he suggests may seem like overkill the principles are important, miinimize friction at contact points, minimise excess length behind saddles, locking staggered tuners if possible etc
Worth a look even if you don't use every suggestion
I remember reading magazine articles where Van Halen described his tips for keeping a Fender Strat vibrato in tune. You will find most of them in the video at the link Jeff provided. The highlights of Van Halen's tremolo set up, as I remember them, are: