Rock wool type (Paroc)

[sxx]

Hello,

I'll have good prices on 2 different type of stone wool to build the studio:
Paroc eXtra : 28 Kg/m3 - Lambda: 0,036 W/mK - air permeability : 120*10-6 m2/sPa
Paroc eXtra Plus : 30-35 Kg/m3 - Lambda: 0,034 W/mK - air permeability : 100*10-6 m2/sPa

Which one would you recommend for sound insulation? (7cm thick wool with 8cm air gap)
Which one would you recommend for accoustic treatment? (broadband absortion, 15cm thick wool with 15cm air gap)
Should I spend a little more money and buy a different material for one of those treatment?

Thanks for your help!

[sxx]

Also do you think that the Paroc eXtra : 28 Kg/m3 - Lambda: 0,036 W/mK - air permeability : 120*10-6 m2/sPa (=8.325 kPa*s/m2) is a good choice for superchunks?
(triangle side=60cm)

Otherwise, I was thinking about this one which is available in Switzerland (but more expensive)
http://www.isover.ch/fr/products/pb-m-032-0