Single vs Dual steam heads
There are 3 different steam technologies at this time so with different killowatt sizes you may want to go with 2 steam heads instead of one.
With the single tank pressure cooker type that let the whole load of steam out at once, unless you want your feet to get. burned, never oversize them. Many people have high ceilings and the only way to avoid the steam trap is to oversize without a fan. You will need an enclosure to go around the steam head if it comes out too hard. Also, having 2 steam heads should make it much quieter than having one steam head if you are getting a steam generator over 9 kilowatts.
For the dual tank models, these always have 2 steam heads. One for the larger boiler and one for the baby boiler. If you are getting a larger sized generator, make sure you know how many cubic feet it goes up to. The higher psi models usually make a dryer steam with less condensate and blow harder and might burn your feet a little but the 10 and 15 psi models let out more condensate and don't blow as hard but the room feels hotter since there is more water in the steam. But, it falls to the floor and sticks to the walls quicker than the dry that lingers more in the air.
With the atmospheric tanks (non pressurized steam generators), these always require 2 steam heads if you go over 9 killowatts. Having 2 steam heads makes it whisper quiet, especially if you are using 3/4 inch pipes and not the smaller 1/2 inch pipes. Also, when having 2 steam heads it makes the steam not as clumped together.
So, if anyone is getting a generator over 9KW, if not getting a dual pressurized type, you can use a single or dual steamed. (You can't go by what your see in the gyms and spas. They have 1 inch pipes and can handle just one steam head. Most homes have 1/2 inch pipes. So, if you really want to make it whisper quiet and want a high quality steam, make sure you find out if the generator works with 3/4 inch pipes. You never want to use an adapter if you have 1/2 inch pipes and make it work with a 3/4 inch outlet on a steam generator.
Note: Be aware that if you have a 10.5 KW or higher and you've upsized 30% or more for your adjusted cubic footage (ceramic tile 30%, glass door 10%), if you only have 1 steam head it will blow twice as much instead of splitting the steam speed coming out. This can burn your feet and it can be a very uncomfortable steam experience every time you steam bathe. If you have two steam heads and they are only 1/2 inch, that can also be a problem.