Canvas theme 3 Column Magazine Grid?

I’ve been attempting to change the Woothemes Canvas Magazine grid style, from it being a 2 column grid (side by side) to a 3 column grid (Full width). I just can’t seem to figure out where the setting, or in the code itself, that is telling it to be 2 columns – because then I figure I could adjust it to being a 3 column grid.

I should note that I’m not talking about changing the layout from Layout Manager into a 3 column grid, i’m just talking about the Magazine grid style.