If you want to get into GameZone posting shape, go ahead and use the GZ during the Grapefruit League games to do so. PBP is usually handled by one person (designated early by said person... in other words, call dibs on it! Or shotgun... or whatever!).
The others can participate in in-game commentary in other threads, but make sure you don't override the PBP. Use the title area as much as possible to give the score. Failure to give the score and details in either the subject line or the body of the text while doing the PBP will get you the tag of "Milo"-ing the GZ. Not good.
Have fun learning if you're new to this GZ, watch and learn from the veterans and PLAY BALL!