For a standard layout i generally stick to a Site Container of 1100 – 1400px.
There popular sizes and within that range the full screen will fit nicely into the most common screen size of 1366px ( Laptop ).
You can still break out of this size and create full width landing pages by using the Layout Meta Box or Layout Element to create a full width container – which is designed for using with a Page Builder.
For single posts if i am not using a sidebar then i will narrow the content (not container) width down to around 720px for easier reading. You can use the Layout Element to adjust the content width for just posts.