What we did w/my Ground Controls when they first went on was to research what an OEM ITR's jack-reinforcement to ground was at all four corners.

Then we adjusted the Ground controls so that the height at all four jack reinforcement points was where the OEM ITR was, w/out counting threads.

Never had the first problem.

This is going to be a little rough, but short of actually having someone help you corner weight the car, I can't think of anything better to do.

Our own Scott Lear has an article on ITR suspensions in the latest issue of Grassroots Motorsports, and you might want to have a gander at that for the benefits of corner weighting.