The reason for posting in Calibre was to take advantage of the smart people here, but mainly because I wanted to see if there was a discrepancy between epub format produced by Calibre and the constraints of Mobi format. But point taken, there are other forums.
I did not find the answer to my specific problem, but found another solution. I should have asked, is there a better display format for the Kindle Fire? The answer was given by wallcraft. I bet there is much better control in that format, but have to wait until it is available to a small publisher (some publishers got it in time to roll out pubs with the Fire's release).
In the meantime, can wallcraft explain "hisrc", I found mentions of it but not the basics.
Originally Posted by wallcraft
The Kindle Fire will use the new KF8 format, see New Kindle format: KF8
. The hisrc approach has the advantage that it works on existing Kindles, and will probably still work on the Fire. We won't know for sure until KindleGen 2 and Kindle Previewer 2 (or the actual Fire) are available.