Multiple nozzle desuperheater valve - Pressure drop and weber number.

[Raai2015]

Hi all , We have the boiler desuperheater control by Multiple nozzle desuperheater valve. I got a offer from two reupted supplier. Below are some details on design case.
Spray flow : 3,11tph
Spec density : 0,95
Cv @ 80% opening : 6,78
Dp offered : 0,3 bar
On the above i calcualted the DP , it was around 0.2 bar. Below are some opinions needed.
1, Both the suppliers give DP across the load same 0,3bar but with different CV --> My view is Different Cv (different opening) results in different DP in principle. May be they specify the max 0.3 bar in all load cases.
2, Interesting for me : this kind of valve (multiple nozzle) suppliers requires atleast 5 bar above the steam line. I was under impression 5 bar will the DP across the multiple nozzle valve. When they have 0,3bar DP across then why do they every time require 5 bar DP atleast?
3, I read somewhere , weber number is the indication of atomization and it needs to be above 12. Does anybody have calcualtion (Dr google is not much helpfull this time) of weber number?
PS : i will be posting this in Boiler group.
Appreciate you opinions.