I found the pennies work except for slop in the front end, like king pins being shimmed exactly the same, or those little balls wearing in the lower arms. I would think "am I testing the tweak or the front end?". I went to a home made tweak station, it seems to make more sense to me. It also shows that I was off with the pennies I feel due to suspension slop even if it is a little.

In MY opinion, Pennies will get real close, but Tweak Station gets you there. Scales are a tweak station too, just a different form. I think 2 scales in the front would work fine.