How do you know the nozzles have the same diameter and internal engineering, and that they deliver the same flow rate as the nozzles in the other head? The key spec is the total flow rate of the head. Also, have you checked your local codes? It sound like you are contemplating a total flow rate that would far exceed code in may localities.

Yeah, this is really a stupid idea all the way around.

We can start with the code issue - depending where you are, showers are strictly limited in total gpm. Second is the fact that it's reprehensible behavior to be building a shower that consumes 10 (or even 5) gpm in water, and energy to heat the water - even if it's not regulated by code.

Lastly, you have to size everything - the water heater, the drain, the supply lines - for that load.

Buildings, including homes, can easily last a hundred years. They need to be designed for their future - a future where both water and energy are more scarce.

Thanks for the info, Karen.

@paco6945

You were given good information and good advice.

You don't seem to have the GPM of your preferred option. If you don't have the actual GPM rating of the showerheads you are just guessing.

Two people have told you to check code.

The supplier, and two of us have said it's a bad idea because you must size everything accordingly. Not to mention it's incredibly wasteful.

I'm sorry you don't like the advice - so keep fishing until you find someone who agrees with you and then go with that.