Most commercial float tanks are about 8 inches or more wide and about 8 to 10 feet in length. They can be as wide as 4 foot or the most expensive ones are 8 feet wide. Doubling the width gives more room to move around and a feeling of less claustrophobic. Truerest.com and floatlab.com are the two places I believe have the best float tanks in the states. Float lab is located in California.
If you want to get a float tank for commercial use, I would like to be apart of the process. I usually can beat the price unless you are buying a used one. Many of the people that bought from me will let you come by and try out their tub before you buy. It is best to at least look at several brands and get a feel for each style before putting one in your clinic. In the beginning stage of promoting these, I will offer discounted prices to get these in clinics. I also work on a small commission as I refer customer to your clinic that contact me who are in your city that want to use your float tank.