Middle name- Judith or Judy?

I asked this question yesterday, but it was while Y!A was frozen, so I only had one answer, so I decided to repost it. Anyway, I'm still not decided on a middle name for Alexandra (I probably won't be until I eventually put it on a birth certificate), but one of my choices was Alexandra Judith, but I like both Judith and Judy. I know I'm a big proponent of "give your kid a full name", but I've always been a little more loose when it's a middle name, so I can't even use my own advice. Which would you use? Alexandra Judith or Alexandra Judy? Last name Walden if that factors in your decision, because it doesn't help with mine. And if you have some sort of particular reason, I'd love to hear it. Thanks!