full width template

I love this theme for its simplicity and lack of bloat and because it lets me make all the choices in a child theme.

However I have a huge problem getting the right combination of templates to work. If I choose full width as a main template in theme options , all my pages and post templates are full-width. If I choose a sidebar template I have the option to make individual pages full-width. I want my portfolio posts and especially the single portfolio posts to be full width, but my pages to have a sidebar.
I looked into the single portfolio template, but I don’t know how to get rid of the sidebar option. I can get rid of the sidebar, but not make the template stretch full-width.Any help?

Thanks