The flow rate specified in their specs is suspect, at least to me. Keep in mind that the Copper Institute's recommendation for maximum flow rate of hot water is 5fps, and on a 1/2" pipe, that equates to 4gpm, so I'm not sure how they say you can get nearly 11gpm out of the thing. Exceeding that rate can lead to flow noises, excessive pressure losses, and in the worst case, literally eroding the inside of the pipe away. Most everyone else's 1/2" valve is in the range of 5-7gpm, which, once you mix hot and cold, seems reasonable to me (and often spec'ed at 60psi). 3/4" valves are usually in the 10-14gpm. If all of yours were on, they're rated at 7gpm, which is pretty much the limit of most 1/2" valves, and likely you'd see some reduction in the spray strength if all were on at once. Sprays (except for the rainhead) rely on there being more flow than the restriction will allow to pass through. The Bernoulli effect causes the water to speed up through the restriction. If there's no restriction (i.e., not enough water to effectively backup through the restriction), there's no acceleration. Most people express that as a loss in pressure, but in reality, it's a result of the water not speeding up. Think of a hose without a nozzle...the pressure is the same, it just goes faster when you put a nozzle on it that restricts the flow.
Their factory calibration seems to also represent unusual water temperatures. From their manual:
Factory calibrated inlet conditions are: Hot and cold water pressure = 43.5 psi (300 kPa) Hot water supply temperature = 149°F (65°C) Cold water supply temperature = 59°F (15°C)
It would be very rare for a home to have 149-degree hot water, and at least where I live, wintertime cold supply I've measured at 33-degrees F, so I'm not sure what that would do for your outlet temperature range and control.
Their installation instructions are deficient on the proper way to include volume controls or diverters. Sorry, on that, I can't help. Some thermostatic valves want the shutoff before them, which would seem to dictate a diverter, while some can handle it after. If it was in the installation instructions, I missed it.
