HPM bump steer

The guage will tell you how much bump steer you have.
If you don't know how much you have to start with, how do you know you need to adjust it? Or how do you know how much to adjust it?

If you don't have a guage, or access to one, leave it alone. You could easily make it worse.
 
Nope, they probably won't. I've been racing cars for about 13 years, and most teams I know don't have one.

For the most part, bump steer is only noticeable in extreme cornering. I honestly doubt most people will ever tell a difference on the street. If you feel you need to adjust it, and don't want to buy the gauge and figure out how to use it, I would suggest finding a race car set up shop in your area.