Gridmarket header.

Hi, I want to create a default theme for shops in Market press using the New Blog Templates plugin.

Specifically, I want to have a set custom image header for all new sites created and the each new site to have the option to be able to add custom text to the header.

I notice in grid market, which I am using as a base, you are unable to select custom header image and text at the same time.

Am I looking at hard coding the header image or is there any configuration of options that will allow me to achieve this.

Thanks