Maximizing space layout on a plane

I need to add parts that will come off a press and stack on a cart. I would like to try and maximize the space that is allotted. Is there a way in solidworks to do so? I haven't been able to find much on it. Pictures are of the cart where the shelves will lay, and of the shelves themselves (needing the layout). Worst comes to worst I will manual add in a layout.

Thanks in advance.

SolidworksAssemblies