Quesion is the resolution. I try to set toe as close to zero as possible so need resolution to 1/32" at least. Camber should be marked in at leats 1/4 degree and preferably 1/8 degree increments.
Since toe is essentially measuring the distance between the front and the back of the front tires, where you do it does not matter too much. To set camber properly you must have a level surface (fortunately my garage floor on the left side is almost perfect), so just a camber guage is not enough.
Note a good one will allow you to set both caster and camber.
All of that said our 90 has almost 2 degrees of negative camber in the rear but the radials wear evenly (and after 40,000 miles on this set, I'd know). I set the 88 as close to 0 as possible with shims but probably should not have bothered.