Your best bet of to go to gssfonline.com and read all the rules. You don't need a holster or mag pouch at all. Most people recommend having four magazines loaded before shooting but I think you're only required to have three.
It's not the same kind of competition as IDPA or USPSA. You start with gun in hand, shoot magazine, that's the end of the round. Then you can reload and go again.
Hockey, I am thinking of coming over and shooting the Orlando GSSF match this year. What equipment do we need or can we use? I have typical IDPA/USPSA holster & mag pouches. How many mags can we carry, etc? Thanks