Raid Mob Spawns Adds

[merb]

So I am trying to get a raid mob to spawn adds at certain amounts of HP. It breaks down like this:

75% = 3 lvl 68 adds
50% = 5 lvl 66 adds
25% = 8 lvl 65 adds

Now, I'm not too good at writing quests, so I was using GeorgeS's quest program as a template for this.

sub EVENT_COMBAT {
 if ($combat_state == 1) {
  quest::setnexthpevent(75);
 }
}

sub EVENT_HP {
 if ($hpevent <= 75) {
  quest::spawn(999270)
 }
}

This is just the 75% HP event, and if I can get this part working, the other parts will be ok. What I really need help on is the quest::spawn part. The 999270 is the first set of 3 mobs. Now, what am I supposed to be putting for the "grid" and "guildwarset"? I was thinking to just put 0 and then the x,y,z.