I accidentally let my macbook update to iTunes 14 and I need to get 13.1 back.

iPod 4G; MacBook Pro 13" form about 2006.

Last year, I allowed iTunes to update itself to vs. 14. The "update" broke my computer's ability to sync my iPod. After over 20 hours of solid heartbreak, profanity, unnecessary restores and resets (including total factory resets of the iPod, since at first I thought that was the problem), and the loss of a fair bit of data, I finally learned what the real problem was: iTunes 14-- and some helpful person posted exactly how to remove it and re-install iTunes 13.1, which I did. That fixed everything, except the data I lost in the process which is lost for good.

Now, somehow Update reset itself again, and before I saw what I had done, I clocicked "OK" and it has "upgraded" once again to the broken iTunes. I know this can be fixed-- I have the dmg from last time, but there were a handful of fiddly little system files that had to be removed at all for the new install to take, and I can't find that list.

Somebody, help!