I think I'm pretty much in line with what you've said. I report obvious bounty spamming simply as "low value spam" or similar, but anything more complicated (such as rehashed content), I include a bit more information. As I said, my "bad" reports are currently sitting around 0.2% of my total, but just wanted to make sure I wasn't making life any harder for the mods than it needs to be. Thanks for the clarification.

An additional little suggestion that might help: Expand the comment box on the reporting page. I've since started using a script to do that automatically, but it's really difficult to write a meaningful comment to the mods, especially one that needs to be a couple of sentences long, when you can only see ~40 characters at a time.