Just deck the bridge, add two more springs, screw in the trem spring claw a bit and remove the tremolo bar (whammy). I do this to all my Strats since I play them as if they were hard tails. Tuning stability and overall feel is practically identical to a true hard tail with the added benefit of keeping the stratocaster sound.
I recommend simply sticking a chrome knob between the sustain block and body to lock down the bridge. Then remove the trem spings. It sounds and works nicely and takes 2 seconds.