Like Spider-One said there is an angle that's offset to help compensate for road crown. That angle is caster, the compensation is your "cross caster" between the front tires. I go into greater detail in this thread
http://www.fordraptorforum.com/f7/your-raptor-its-alignment-539/
The compensation/cross caster will affect how the vehicle tracks on a flat road, so you do have a happy medium. I know the roads where I live are so uneven, from one part to another, chasing after a perfect cross caster value is pointless. What you can do is set the truck up with a greater overall positive caster(within reason), and slightly toe'd in/positive toe . Both these will help with tracking on any road.
With the perch mod, you will loose a good bit of possible adjustment for positive caster, because you are using that adjustment to adjust and correct the negative camber angle that is resulted. The higher you go, the more you loose. Because of this (as far as caster angle is concerned), you will loose some stability/tracking.
You get one warranty/free alignment up to 12,000 miles or 12 months. Depending on how many miles are on your truck, it maybe best to wait (unless it's really bothering you, or noticeable) before you get the warranty alignment checked/done. The suspension's still settling/breaking in even after a few thousand miles. If you were to get the alignment done while its still breaking in, chances are it could be out again once its had time to break in. It's best to let things settle before you go adjusting.