Thanks again, David - more useful ideas to think about.
I initially set the margin as far to the left as it would go, then clicked the + icon twice, and left it there while testing each of the margins. For some of them I noticed that the margin had reset itself about a quarter over from the left, but didn't do anything about that. It didn't seem to make any difference with the links, but I didn't test it. In fact I remember now that in one of the testing sessions not only did the indicator on the line move over but the margins of the ebook became very wide. I just set the margin back to +2 and started over.
The page numbers are not visible on the ebook right side margin as they are in ADE. There is a message at the bottom of the screen (taking up valuable reading space) saying PG 3 OF 13. Is this the page number you mean? Is there a way of turning this off?