What step and repeat banner size do I need?

It all depends on how many people you would like to pose in front of the backdrop at a given time. Through Essex Banners you can order 4 different sizes of step and repeat backgrounds:

7 x 7: up to 3 /4 people

7 x 8: up to 4 / 5 people

7 x 9: up to 5 / 6 people

7 x 10: up to 6 / 7 people