In practice, the section names LEFTCOL and RIGHTCOL do not work well (for 2 column definition) when the other definitions use COL1, COL2, etc. It makes it hard to switch layouts. So these should be renamed to COL1 and COL2 as well.
And the templates should ignore missing section names to create empty columns.
Added examples.
-- ArthurClemens - 02 Jan 2010