Thank you all. I'm not totally sure what I'll do at this juncture. I also had a chat with a particularly thoughtful "genius" at the Apple Store. We had a good chat about the rise of converting DVDs and CDs to our hard drives, and how this has resulted in a lack of space for many users. In other words, he normalized the problem, and also made some space-saving suggestions.

There seem to be multiple sensible solutions. And a DIY swap doesn't look particularly terrifying. Likewise, the Apple Store recommended two particular third party stores in town. I'm sure I can make this work one way or another.