Greg makes a good point about having it professionally done. They have better equipment. I do mine at home just to get the car on the road. Most times it's good enough but it's probably not as good as a professional could get it. To address a couple of your concerns; First, you don't need to pop off the rod end of the tierod because they have forward and reverse threads so when you turn the collar it shortens or lengthens on it's own. Second, when the wheel changed position after alignment, it was a warning. Something is very bad on your front end. I could take a guess at what it is. Since you probably have looked at all the parts and do not see an obvious problem I'll shoot for something that's hard to see, the lower control arm bushings. These can be bad and it's hard to detect.
