bad table with with latex writer

With rst2beamer, I'm getting table widths that are far too narrow.
It looks like this is coming from the latex writer (specifically,
get_colspecs).  It appears to produce only about half of
the \textwidth as the table width.

Unfortunately I am in the middle of a project and cannot explore
this further at the moment, but my workaround has been to set
the width on the table to far above 100%. Perhaps this report
while inadequate will be of some use.

Best, Alan Isaac