I'll answer my own question: My right testicle is quite a bit larger and hangs lower. As I understand it, I'm in the minority but I'm interested in what others say.
If you're female, I'd be interested in knowing whether you notice these things, and interested in any data you have.
One reason I ask is … this will be a topic in a story series I've been writing the past several months. It involves a female pre-med student who is very straight and her “friend” the bisexual college baseball player. There will be many measurements. More on that to come.