When you make a copy of a Roman mosaic should start on a small detail or a full floor? You are always working on a full floor. You might only have a small panel in front of you but you need to visualise the rest of the floor going out on all sides.
This is because your way of working should always be the same, whether you are setting 250 tesserae or 250,000.
Creating a Roman mosaic is not just about applying the Rules to your work but it is also about the way you work. Working at speed, not fast but at a reasonable rate, does show in the work and does explain some of a anomalies we see in the mosaics.