I went with a 1.3mm cometic.
Most people go with a 1.2-1.4mm
This depends on many things including, but not limited to; the type of piston you are using, the fuel you are using, the boost pressure aim and what you want from the engine. I decided on a static cr based around the above factors and made a decision based on that.
If you have performance cams, you should consider the dynamic cr too. As I'm using stock cams, I didn't worry too much about that on my build.