How to "rough in" front end alignment after rebuild?

Level, Tape measure , 2nd set of eyes.
Make the wheels/tire look 90 to the ground with car resting and bounced to settle.
Set the wheel tow straight with the left/driver 1st..then dial in the pass side.
You won't get all right, just close.
The strut system on newer cars is much easier because you can just 'if the entire suspension isn't worn' mark around the nuts n washers with a sharpie and simply reinstall them inside/lining up with the marks.

Good luck