Ok This is my suggestion.
Look at this link and select the beer type then set your CO2 based on the temp you plan to store the keg at for serving.
If I was to do this i would shoot for 2.3-2.5 volumes of CO2 ~ 12-15psi
The German one of 3.6-4.5 is way too high unless you have oodles of beer line (like 50') between the keg and the faucet. If you don't it will just shoot a glass of foam until you blow through the whole keg.
12-15psi is high for mine with 5' of 3/16" beer line from keg to faucet.
ABSOLUTELY ESSENTIAL - DON'T MESS THIS UP! BE SURE TO VENT THE KEG BEFORE ATTACHING THE LOWER PRESSURE GAS OR BEER WILL GET IN YOUR GAS LINE!
- Carbonate at 12-15PSI.
- Then at serving time disconnect the gas or shut it off.
- Vent the keg.
- Dial the regulator to something like 5psi (or lower) then reattach the gas line and serve. Set it whatever is high enough to serve it without beer gushing out the faucet or delivering a ton of foam.
I have done this mistakenly more than once. Its aggravating to try to clean and dry the gas line. This usually only happens on full kegs where the bottom of the gas tube is below the fill level.