This is from a person who is truly lopsided but not because of Tracy's methods. My dd refused my left breast from day one and I was trying to get her on this less preferred without any luck. After 3 weeks of fighting with her and eventually putting her on the right one only, I even stopped pumping and decided that the right breast will have to be the only one she feeds from. It worked great, in fact she was always on the top of the charts. My non-producing breast is my normal pre-pregnancy size and the right one is bigger. I used to be much more lopsided but now they don't look so different any more (my dd is now 18 months). When it was more of an issue I was putting a pad to make them look same size. And I got used to it LOL. Anyway, after you stop nursing your breasts are supposed to go back to its original size.
Now, being a moderator for this forum, I haven't noticed any unusual number of women having this problem. I think, your breast adjusts to demand and it doesn't matter if you nurse from each breast at the time or from one only and then from the second one at the next feed because eventually you will offer each of them to your baby. I also belong to another forum where moms offer both breasts at each feed and they also have problems with being lopsided. It just happens to some women, for reasons you mentioned, one breast produces more, or because of baby preference (which may come and go).
Also, many women here, feed from one breast only at the beginnign and when their baby hits a 3 months growth spurt they start offering a second one to satisfy baby's hunger. This is actually common here and you should follow your common sense. Also, there are BW moms who don't single side feed at all and do what their intuition tells them is the best in their paricular situation.
This is my take on this. Hope I helped you a little.