Let's say I'm describing changes in a new version of some software. This software, in particular, deals with entities called classes. For this question, it's only important that a class consists of two parts: a header and a body. Now, let's say I have a sentence like this:
We've improved the visual separation between the header and the body in classes.
The choice of articles in this sentence is simple so far: "the" is used with "header" and "body" because they're unique in the context of a class. But what if the said separation has been improved only for a special case where the header is multiline? I'm having trouble with finding the right wording for this and especially with getting the articles right. Here are the options I've considered:
(1) We've improved the visual separation between the header and the body in classes with multiline headers.
This one looks almost okay to me. However, doesn't "classes with multiline headers" sound as if a class can have more than one header (which is not the case)? Although other phrases with the same structure, e.g. "people with big heads", don't give me that impression, I'm still not sure. Are my doubts unreasonable?
Besides, I don't like this option because it mentions the header twice, which seems redundant. I would avoid that in my native language. That's why we're moving to the next options:
(2) We've improved the visual separation between the multiline header and the body in classes.
That's where I got stuck with the articles. "The" looks wrong because "multiline header" (unlike "header") isn't something that exists in every class. Is this the right logic for ruling out "the"?
(3) We've improved the visual separation between a multiline header and the body in classes.
So what about "a"? I have to use "a" since I can't use "the". It's logical, but somehow "a multiline header and the body" looks strange to me. I can't remember seeing such a combination of articles (applied to different parts of the same thing) in texts I read (which probably just means I should read more and pay more attention to this kind of grammar). So is this one correct?
(4) We've improved the visual separation between multiline class headers and bodies.
This one sounds like the bodies are multiline too.
(5) We've improved the visual separation between multiline class headers and the body.
This combination of a plural and a singular looks strange to me too.
Please help. I set the questions in italics. Also I would be glad to know your opinions on what the most natural way to phrase this sentence would be.