You answered your own question. The only way to do that install properly is to move the perches to the A-body width. And yes, having worn out bushings can add to the problem, since it's unlikely they're worn exactly the same. Of course, if you install new bushings, you'll force the springs to take up more of the difference caused by the incorrect perch location, so, they'll twist more. And you'll wear out the bushings faster.
