String and bridge alignment is easy
take another bass and measure the E and G string lengths,
set the saddles to roughly same place on the base plate of the bridge
position the bridge so each outer saddle sits the same distance from The nut as on the other bass. Put masking tape in front and behind the bridge (on the body) in case you move the bridge
Attach old strings to tuners (or tuner holes) and thread over the saddles and use the strings to get alignment correct over pole pieces - mark the screw holes through the bridge onto the body once you’re happy
Rough and ready, but it works