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My understanding is that the sourcing model in GEDCOM (ie, the data that is captured about sources of data) is essentially modelling published books. To that extent, it is closer to the academic sourcing patterns, which seem to major on printed books and unpublished dissertations.
GEDCOM based software like FH therefore produces its printed citations by roughly, vaguely, sort of, shuffling the elements of the source model that is describing printed books.
I mention this to explain why FH and GEDCOM do what they do.
To a large extent, the GEDCOM sourcing model for simple books can be extended by doing things like sticking extra stuff into the Publication item - it is, after all, free text. That way, you can extend the simple book model to cover a book published on CD or in a website such as Archive.org by compacting the two sets of publication data together, linked by some words to indicate which is which.
The essential issue with genealogy sources is that most are unpublished and so don't fit the simple book model because there are other things that we need to capture. You therefore have two basic choices in FH. These other things can be mashed up and fit into the book model and seeing what these print like in book-like citations in reports. Or you can follow ColeValleyGirl's approach of putting everything into a single item and setting FH to only print that item. (I follow the first pattern but wish I could have done the second. Too late).
As for ESM's citation formats - I have huge respect for her work. But, I can look at her citations, see a list of items and not have the faintest idea what each item means. My own citations use a lot more connecting words and phrases like "summarising", "previously published by" etc. The other thing that people miss, including her devotees, despite her emphasising it again and again, is that her formats refer to the final printed form, they don't say anything about how to enter the items into your system, so please don't imagine that you will learn that from her books.
All this is just me trying to give you some background insight that helps me at least.