iPhone: Sync music from one computer, everything else from another

It is actually pretty easy to sync an iPhone (and, I imagine, an iPod) to different computers. There are a few tricks to remember:

• This only works if the data you want to sync is cleanly segregated between computers. In our house, we have all our music on our server, and our calendars, apps, photos, and such on our individual machines. If you want to try to sync some music from one computer and some from another computer, you’re on your own.
• iTunes will give you a stern warning that you’re about to erase everything you’ve ever owned in your life, or something like that. Don’t be alarmed. (As long as you’ve just backed up your data to your “primary” computer.)
• Did I mention you should back up your data to your primary computer first? That’s because …
• … perhaps you may have, hypothetically, in the past, used an app like JHymn to let you play your iTunes store purchases on a non-Apple device. If so, and if you sync one of those songs to your iPhone, iTunes store app purchases may no longer launch. I’m not going to investigate further to see if that’s really what caused the problem, because I don’t want to spend the time restoring my phone to its previous state again.
• Just to say it again: You may no longer be able to launch any iTunes app store purchases. You should be able to restore your iPhone to its previous working state, however.

If all goes smoothly, you’ll see that iTunes on the “secondary” computer has its “Sync music” checkbox checked, while it’s unchecked on the “primary” computer.

If you try this, let me know your experiences.