I am using writematrix() in my code. I had the same problem James describes above - column width uncontrollable and oft times too narrow.
I found a 'nice' workaround:
For me, titles for columns would end up truncated because cell widths (columns) were optimized for the data which took less space. The solution was to write the titles last, after all data was written. Titles are still at the top of the column for me, but now the width is adjusted for titles.
In other words:
Write your longest data cells last - even if those data elements show at the top of the excel worksheet page. The column of data cells will now be formatted to fit the data requiring the widest width.
