Thanks for the reply. My problem is not with the markup in the tables, I think, but with ADE and its odd treatment of tables in epubs. Also, the option to increase font sizes (magnification) of the text in epubs causes problems with tables. I may go with tables, anyway, but I thought I'd just try svq.
Apparently, though, svg is not recommended for epubs. One epub available on the web that originally had svg has replaced those illustrations with jpg. It looks like svg is a dead issue with epubs.