To have your FR bridge in the correct position,it should be hanging parallel to the guitar body .

For heavier gauge strings , you'll need to screw the spring holder more into the guitar body to get the Bridge back down ... If you reached the max screwing point , you probably need to add another spring.

For lighter gauge , you'll need to unscrew the spring holder away , to get the bridge up again ... If necessarily , you can remove a spring.

Usualy , 3 springs works cool for .009's gauge , and 4 springs for .010's gauge .