As silly as this sounds, after I rebuilt (bushings, ball joints, shocks, extended rear upper a-arms etc.) my suspension, I used an straight edge (against rotors), a ruler and my iPhone's built-in level. I got everything where I figured was pretty close to spec (after a bit of adjustments to get the perfect ride height) and headed off to my alignment shop. Turns out I was a total of 1/2 degree off on my toe-in and my passenger rear upright was off by 1/10 of a degree (yes, a tenth). That was it. The rest was perfect. It frankly could not have been simpler, or much more accurate either, as it turned out.
Mark