Has any one done a dual stage water/alky injection instead of progressive?

I have seen the http://www.coolingmist.com/
setup and they have a dual stage kit where you have a lower
flow nozzle at lower boost and at higher boost (using a second
selonoid and pressure switch) a second nozzle kicks in.

Would you say that this is a decient alternative to a progressive system?

If I am DYI a system would you say that this is just over kill?

If you are using water/alky injection what are your thoughts?