That's a very comprehensive article! It's not an easy task that you've set yourself either
My suggestion? Be clear at the beginning who this guide is for, what level of experience does your target audience have? If it's complete beginners, then a fair bit of that information information will be over their heads or not in a context where they can get it into their sphere of knowledge. If it's for people that already have some experience and have other machine tools then they'll already know allot of it, but may not know what you mean when you say "get a mill with the same capacity as your lathe".
It's also a risk (and one that I'm frequently guilty of) in such an information heavy field to make such guides a list of information. That information is clearly useful, otherwise you wouldn't have included it, but your reader may not understand why it's useful. Why do you need to have your mill in tram? How do you do it and what do you need?
It may be more useful to divide the article up into sections, such as " just starting out with machining, what are the big things I need to know about mills ", " got some machining experience but can't tell between a knee mill and a bed mill, let alone why I'd want one over the other " to "now I know what I want, how do I find what I want without getting a lemon". That way you can also tailor each section to a particular audience.
It's really hard to teach a subject that you know very well to people that don't know it at all as they have none of the assumed context that we have accumulated over the years (as I was told in some of my teaching feedback). It's quite a trick to put yourself in their shoes and figure out what they need to know and how to reach them it!
