The ideal Strat setup should be a floating trem setup... for most styles of playing. It sounds like your bridge may be floating a little off center though... Since you can sharpen notes a lot more than flattening them. Normally you would want it slightly offcenter the opposite direction... Atleast, that's how Fender would set it up at the factory. If you find yourself not using your trem that often... I would highly suggest putting the other 2 springs on there and just leaving the bridge flat against the body. This gives much much much more tuning stability. But you sacrafice the efficiency of the trem itself. A number of flags are raised by your issue though... Some things to consider... If you ever chage your strings to a higher gauge... it will cause your bridge to sit at an even greater angle... and if you already have your trem springs screwed in as far as they go... you're going to have your hands full trying to set that up. Ideally though, you don't want to screw your springs in so they are taking all the load of the strings. Right now it sounds like the tension of your springs is greater than the tension of your springs... It should be an even trade off.... But, if it's not bothering you that much I would just say save yourself the worry and make due until you need to fix it.