@KevinH
Personally, I avoid editing plugins. I would rather try to accomplish an edit using a S&R Regex. Weirdly, I actually enjoy it when I can complete a relatively complex task with some simple regex and logical steps. It's a bit of a challenge.
I am in no way against plugins at all.
Doing it this manual way, I can see what is changing and why I need to change it, and that gives me a much better understanding of html, css and the other aspects of ebooks. Plus, having done it this way for quite a while (going onto 3 years), its second nature and I do it with barely a thought.
Simply pressing a button is no fun