Hi
You've done the right thing, by looking ahead with your layout, to see what size peices you have around the room, but sometimes it's not possible to avoid a small peice somewhere in the installation. Those small peices have just as good a chance as the rest of the tile if you set them properly, so you shouldn't worry about that. If the rest of the layout looks good to you, then it will be fine. In the end, you'll be the only one who notices.
