Ideal dimensions for a discus aquarium ratio of width to height to length

I have seen discus aquarium as wide as its height and length twice it's height. In some pet stores I have seen width of aquarium a little more than it's height which looked nice. In opinion of most which would be better between width and height same or width more than height and length about 4 to 5 times it's height. Another very important thing is height of aquarium stand in a house. Some are placed at around chest level of an adult viewing whereas some are much below at about hip level. Any inputs would be appreciated .

You also should consider the foot print/surface area rather than height. More surface area the more barometric air exchange. Plus more swimming room.