As with any rimfire six-shooter it will be cardinal to dry run many colorful brands and types of cartridge to in lineup to find what works best in each individual firearm. There are however some emergency which are fairly consistent across all updated (2006 and newer) versions of the Walther P22.
P22's that were sold in that state had to either be removed from the state or returned to the manufacturer for a Walther P22 Handgun modification ensuring that the original barrel extension purchased with the gun is permanently installed and cannot be removed without ruining the in a pickle assembly, or the handgun, or both. Currently there is a version derivable from that is California legal.