Adjust sizing of header ‘logo’ section

Hi SiteOrigin team,

Thanks for creating Vantage!! I need help to adjust (minimise/remove) the margins of the top section.

1. I have uploaded a web banner image want it to go across the entire header of the website and not allow any white spaces. How do I do this?
2. As my purpose is to display a web banner on the home page, what is the recommended image size to achieve this? Currently the image size I am using is 1900×500 (rectangle) however, this renders lots of white space on all 4 margin sides.

Hope to get your reply asap, thanks – Prash