Center or Enlarge Featured Image?

I have both sidebars activated because I need the widgets for my Google ads, links to my apps, and for a sign up for my mailing list. Since the left sidebar doesn’t show up on the homepage, it makes it easier to prioritize what goes where. On the individual articles, however, it really jumbles everything up because it also throws in related posts. On top of that, the test from the article doesn’t wrap around the related posts, so the reader actually has to scroll down to read the article. I figured out how to remove the related posts, thinking that would free up space for the featured image but it doesn’t quite work that way. Yes, the text is right below the featured image now, which is a good thing, but the featured image doesn’t fill up the space that’s freed up by the related posts not being there. Is there any way to center the featured image or make it fill up that space?

The web site is ForTheLoveOfTech.com

By the way, this is a fantastic theme. I’m just trying to work out the kinks like this one and the fact that submenus show up on the next line. There was some CSS code that I used in my previous theme, which was the stock Twenty Fourteen theme to center the featured image, but that doesn’t work anymore with this theme.