Zero camber can lead to a lot of tire roll-over, which is not good for handling other than in a straight line [which is really just more rolling resistance].

4 wheel alignments can be done using nothing more than a good measuring method and a known centerline of the car [or measured since the unibody is nearly symmetrical anyways]. I'm not saying that this will give you the most exact results, BUT, it will get you close enough that unless you just want the computer print-out telling you exactly what your before and after setups are/were, then you won't be able to tell much difference.

I've been doing car setups for over half of my life, and not once have I worked with a team that had to break out a set of lasers to make an alignment change to suit a given track...