Thanks, Tex and Kevin.
Crap: I just wrote a decent, lengthy post with a lot of info, clicked "go advanced" and lost it all after I had to log in again. DOH!
re; Index: I assumed I would have to add the "See also" after finishing the index because it made sense that it would just get erased with each overwrite. I can live with that.
I'm taking the word for word link coding approach. Very tedious, but if I get through this process once, I won't have to do it again.
I used Affinity Publisher for the print book layout. Excellent and cheap, BUT it does not export to anything but PDF for now. I have Scrivener, but I tried SIGIL because I could see that Scrivener was going to be a struggle in not offering me a WYSIWYG experience on the fly.
I also can't code my way past "Hello World" so I don't really see myself doing anything beyond my current skill set —*a few GREP searches whose successful outcome is often more the result of dumb luck than skill.
I'm going to reread your posts. You've given me much more to think about; including the usefulness of indexes in a search friendly environment. But then again, mine is a social/human psychology book, so it merits a little bit more work to flesh out. It has a glossary, too, so I can't really scrimp on the index too much.
Also, I like SIGIL because it allows me to bounce back and forth between the programs I'm used to using for web coding. I do know my html and css, so at least I'm lucky there.
Thanks again.