Never shot a Garand match. Do they load 2 with a clip of eight standing by for reloads for 10 round strings? From this
looks like they are 10 round strings like Highpower Service Rifle Matches.
Slow fire is single load, and for rapid fire (sustained fire) you load 2 rounds and then reload with a full clip when those are gone. Someone there will show you how to make 2 rounds stay in an 8 round clip, but basically they are crossed in the center and clip tension holds them there until they go into the rifle. They are pressed in just like a full clip, BUT
the bolt will close easier and faster with a partial clip so watch that thumb!
You don't really need any but the regular 8 round clips. They do make special 2 round clips, but you can easily get along without one, loading the 8 round clip with 2 as described above.