I'm replacing panels by attrition (as they wear out) so am really trying to move over to the 4x20 panels so I don't have to plumb so much or connect together. Its all hard plumbed so it makes more sense and looks neater to have just one larger panel on each side than 2 smaller. (we currently have 2.5 left working of the 4 - 1 has just seen too many years, the next one is on its last leg. Even with proper care, they wear out.