So far I have always worked with Sigil (code the tags in Notepad++ first because I customized the syntax coloring, using a lot of autohotkey scripting for auto-typing).
I always make a separate file for each chapter / story, so that keeps the file size down.
I will give those tools a try and see what happens. Thanks for the suggestions.
What I also need to find out is if there is a recommended maximum number of classes in a CSS. One thing that is a contradicting issue is that everyone says "don't use empty paragraphs with nbsp;, style a div or a paragraph to make a larger top margin." But maybe I only need that style one time, and further down the page I need a different one-time style, etc. And before I know it, I have a dozen styles with one-time use. (well, not all for top margins, but just in general). Any advice for that scenario?