@Ross at Play
What you are doing here is exactly the same as what you (reasonably) complain about DS (among others) doing to you - the effect is you're shutting down an exchange because there's no perfect answer.
Note: Switch already answered this, so my rant doesn't really have much bearing. Still, it incorporates my frustration with CMOS. But, since your intent was to demonstrate that it's advice was not helpful, I recall my rant. :(
You're correct, and for that I apologize, but your first 'go to' source always seems to be CMOS, despite no one on the Forum agreeing with it in most instances. I can understand why you'd start there, but you'd do better if you started where most of us end up, at grammar girl, and you'd lose a lot less time.
My point isn't that CMOS doesn't have very useful points, it's always been that CMOS isn't concerned with works of fiction, so there's NO way to evaluate their advice. Without a way of differentiating one guideline from another, it all ends up a gobbledygook, going in one ear and out the other leaving us none the wiser. The information is intelligent, but without a way to evaluate it (ex: such as "this is ONLY for fiction", or "this ONLY APPLIES to historical research"), it's meaningless.
It's not the research you complain about, it's its applicability. As such, our discussions would move faster if you referenced more relevant sources (i.e. those who specifically address the differences between fiction and non-fiction (as well as British and American) uses.