In the hubskiverse six months is "super-old" I guess, but thanks for revisiting one of my favourite threads.

There really is no "correct" with most of this stuff.

If you read down the thread, you'll see a lot of disagreement with that statement.

There's better, there's worse, and there's different, but beyond that it's your choice and your power as the writer to bend this stuff to your will.

Unless you are writing for an audience that you want to please. You'll find that your audience does not want its reading interrupted by inconsistent usage. As you bend this stuff to your will, your audience might want some familiarity. If you don't care about the audience, bend away.

The fact is that written prose doesn't actually match very well how we think or how we speak.

Written prose is a different thing from spoken conversation. Written prose is not trying to be spoken conversation. Spoken conversation when written is indicated by quotation marks and indentations for each speaker to make it easy to read as conversation.

One difference between written prose and spoken conversation is this: In a conversation, the person is in front of you. If you don't understand what she is saying, you can say, "What do you mean?"

In prose, if you don't understand, you go back and read it again. If it is written badly, you throw it out. I think that we agree that the goal, in either case is to communicate. The problem comes with your phrase "broadly appropriate way." Another way of defining "rules" in writing is "best practice," a term they use in health care, education, and other places. What is the best practice that will make your written prose most readable to most people?

Best practice, correct grammar, proper usage of words (diction), and most understandable word order (syntax) is agreed upon through usage and discussion. I recently came across yet another website called Pain in the English that I found fun and helpful.