We are installing 18" by 18" Montauk blue slate tile in a long, narrow space that includes a family room, small kitchen, eat in area and then into our laundry / mud room. We are trying to figure out the best layout of the tile. Square on square lining up, offset running the length or offset running the width. Feedback on the size of the grout line would also be appreciated. We already have the slate so changing it now is not an option. Sorry about the intended lines - just trying to get sample pictures to post (offset length wise was lined up by our installer so that may look better than the others). We are worried since we are spending a lot of our budget and don't want to make a mistake with the design. Thank you very much houzz community! Any thoughts/suggestions are much appreciated!