Parallax Issues PLEASE HELP

Hi there

How do I ensure that the parallax on my front homepage fits to the image’s height and width - i have tried background small and background full, it is always cut off. Are there specific dimensions the parallax should be designed too? It also then does not fit responsively when mobile view is selected. (IMAGE ATTACHED)

For the Features Parallax - how do I minimize the space between feature widgets? (IMAGE ATTACHED)?

Your urgent help would be much appreciated thank you very much.