Column width in reports

Column width in reports

I'm tring to run reports that export to a pdf document but for some reason i can not get the column width to change. One of my columns is a text field where as the rest are only small pieces of text so i want the text box to take up the majority of the page.
I have read that pivot tables are the way forward but that doesnt seem to work when it comes to report generation and whem i use the specific area defined for column width it never actually has an effect on the report, then when i go back to look at the settings i changed they have reverted back to default again.
 
Can someone walk me through it in an idiot proof way please, because i feel like an idiot!!