Featured content – change number of columns

Hi and thanks for a great theme. I'm using Catch Everest Pro and would like to change the number of Featured contents that are shown per row. In the Theme Options > Home Page Settings > Homepage Featured Content Options I can select how many posts I want to present and also select 3 or 4 columns. However I would like to have 2 columns and not 3 or 4. I have created a child theme could you please point me to which php files I need to add to the child theme and modify to get this to work?