If the factory setup doesn't give enough camber adjustment you can find replacement upper arms on ebay that provide a greater range of movement.
JDM-Performance-Rear-Upper-Camber-Arms-S13-R32
The ones below are cheaper but don't have dust boots and I've been warned about the quality of the rose joints.
http://cgi.ebay.com.au/POWER-SPIRIT-...item56323d41ca
With my Harrison, the offset on the rear wheels won't be a problem - it's the fronts. We can't see how the measurements confirmed by 2 other Harrison builders could possibly clear the front guards on my car. And that's using the same wheel manufacturer (Vintage Wheel Works in the states). So it seems there's quite a lot of variance in the bodies.