You're on the right track. Toe IN is most used on street cars and drag cars to keep the steering links in compression to avoid the shopping cart boogie and wandering. This is the prefered state because any bump on one side of the car will tend to add to this compression, minmizing any influence over the steering. A lot of circle track and tight road course tuners prefer toe OUT instead to keep all the steering links in tension. When you have toe IN, you will achieve this state in a corner as the ackerman pulls the inboard wheel tighter into the turn than the outside wheel. When you straighten up, it returns to a compression state. The switch between compression and tension, and back, can sometimes introduce a bobble in the steering at less than opportune times. Setting the toe OUT keeps the parts in tension all the time and eliminates any chance of this issue in the transition. Too much toe-out, combined with a bump, can lead to unexpected lane changes and swapping of ends. Use with care. True. If you have curvy rockers or a tapered frame, just drop a plumb bob on the centerline of the car and measure from there to set up the strings.