In order to the desired CO2 level in my beer I use the following specifications for a 5Gal Keg

• PSI = 35lb
• CO2 connected to CO2 In
• Pressurize and expel CO2 using the pressure release (repeat 2 times)
• Connect picnic tap and remove CO2 from beer line.
• Remove picnic tap
• Shake keg for 4 mins at 35 PSI. 
• Disconnect CO2
• Remove excess pressure and connect to CO2 at 12 PSI