The WAFER Diffusion Bank is available in thirteen variations in size and shape. If there is a rule, the lightbank should be the same shape and size (or larger) as your subject.
So, faces and fashion need a oval bank and cereal boxes need a rectangular bank. Lightbanks are made to minic window lights, and windowlight makes everything beautiful. Certainly, our 3:4 proportioned Rectangular banks are the most popular and most useful for all-round product and people imaging.
But rifles, knives and fishing rods might need a long narrow highlights from long narrow Strip banks rather than Rectangular Banks. Our Strips are the same length as our Rectancular Banks, but HALF the Width.
People, especially those skinny girls, are long and narrow - if you need good head to toe coverage, but increased contrast across the width of the body, chose a Strip, and not a Rectangle.
Not to forget the little SL (for Still LIfe) for the table top specialist - tiny is better too.