Are you guys deciding on this solely based on looks and appearance?
To my understanding, the geometry and handling changes, scrub radius becomes different -- I would guess it makes sense to actually make some calculations to determine the final geometry and preserve either positive or negative scrub radius. Not just randomly install any spacers.
A zero scrub radius could (based on my "investigative" studies) introduce unstable steering as the tire fights itself. As per the article on H&R website:
http://www.hrsprings.com/technical/scrub_radius