Do you have an adjustable pan hard bar? That could help some as well but I wouldn't stress too much about being perfect. My rear end still sits a 1/4 inch out of alignment from being perfectly square under the body, not a big deal Sent from AutoGuide.com Free App
He's not running a panhard bar on his Fox.
It's common for the axle to be a little off center, especially with fully adjustable control arms. It can be adjusted out, but it's a tedious affair.