layout is really what your theme does.
sure the plugin provides 3 different basic layouts (default, responsive,
grid) to choose from,
but essentially it’s down to the theme depending on which you *might*
have to add some css or edit the templates slightly (that’s why they are
templates).
all depends on your particular scenario
in other words , the plugin provides the functionality, themes do layout
etc with the possibility that you can edit the loop templates to make it
work with your theme