To accurately measure bumpsteer you'll need a device just for doing that. Maximum Motorsports offers one in their catalog here -->
http://maximummotorsports.com/mmbumpstg.asp . I'd also use their bumpsteer kit
http://www.maximummotorsports.com/mmtierod.asp.
You generally only need a kit if you're going to make turns like a race car. Otherwise, it's truly nice but not totally necessary. The lower your car and the more radical your suspension, the more you'll generally need such a kit.
Excerpted from MM's install instructions:
If the car has toe in under bump and toe out under droop, you need to lower the outer tie rod end. If the car has toe out under bump and toe in under droop, you need to raise the outer tie rod end.