Two bushings per arm will get you about 4 to 4.5(at most) at Zero camber, and both sides may not be the same.By the time you dial in a half a degree of neg.camber, and even up the casters,you may be down to 3.5*caster.
IMHO, I wouldn't waste my time with just one per arm,cuz our A's respond very well at 3.5caster,and -.5camber on radials.
With the new settings, bump-steer may become an issue.