The quickest way I've found to position the bridge is with an electronic tuner.
1)Tune the first string open in the normal way with the peg.
2)Then fret the first string say on the 5th fret. If it's out, tune it while still fretted by moving the bridge under the first string till it comes into tune.
3)Repeat steps 1) and 2) until it's in tune both open and fretted.
4)Repeat steps 1) to 3) with the 4th string
The main advantage of his method is that you don't have to think about which way you have to move the bridge