OK, just throwing another horribly convoluted solution onto the pile. I've found that Amazon's Send to Kindle for Mac works for converting these PDFs. I happened to have it installed already (so preferable to installing three extra flaky PDF printer drivers which may or may not work in my case), and it worked fine. The difficult was that getting a standalone PDF was needlessly complex. You can't download a PDF from your Kindle "Manage your content" page on Amazon (AFAICT), so you have to send it to a third-party device.
PDF Documents, including those from the "Send to Kindle" virtual printer, can be sent to a physical Kindle, or an iOS device's Kindle app, but not, inexplicably, a desktop Kindle app, and also possibly not even an Android device (!). So I had to send to my iPhone. Once it's on your iOS device (or maybe a hardware Kindle, I'm not sure), you can download the document, and then use the "Share" link to email it to yourself. Simple!
Basically the steps I used were:
- Print to the "Send to Kindle" printer
- Make sure to select "Archive Document in my Kindle Library"
- Browse to the "Manage your Content" page on Amazon, and wait for the new document to appear in the "Docs" listing
- Deliver the document to your handy iOS device
- Open the iOS device and click the share link
- Email it to yourself
(You might be able to send directly to your iOS device from Send to Kindle.app
and avoid step 3 – I couldn't get that to work, but I don't know whether that was significant)