As a general comment, I think part of the problem with league and self-rating is that people rush into it too soon... meaning, don't give themselves enough time between picking the game up (again), and self-rating / getting on a league team.
If possible, I think a better approach is to play social tennis for a couple or three months first, and then see where things stand. The level of play after three months is going to be much more of an indication of what it's likely to be for the next year. And also, playing already-rated players over the first few months would take a lot of the guesswork out of self-rating.
At least it did for me. I had no idea of what the self-rating guidelines were, but I knew pretty much what my level was based on comparison with friends who had ratings.