On its own, RH will not "automatically insert a huge space
between the end of the text and the edge of the column."
The percent usage for tables is the better way to go, since
that method also produces much better results when printed or when
compiled into a Printed Doc output.
The HTML protocol takes up to the percentage of page width
that is designated, wrapping the words in column 1 if necessary.
However, if there is a contiguous text string
(alpha/numeric/underscore) that is effectively wider than that set
percentage, it will hijack the extra space that it needs from the
adjacent column.
Assuming multiple words, then, a 100/20/80% has worked very
well for us, showing consistency throughout the project, and in
various output. Note also that if your table resides within a list,
it should be formatted as 90/20/70% ( and 80/20/60% if in a
second-level list).
Of course, if most of your content in column 1 is short and
mostly one word, you could reduce column 1 width to 10%, for
example.
Good luck,
Leon