Glavoid is easy to brew but you don't wanna do 3 at a time. The pool can fill up with his shitty gear and force shells out if you kill them all at the same time. Generally if you use an AE within the first few seconds of popping it will force BW during which he doesn't cast or TP. The only complication is that he picks a random immunity to either Magic damage or Weapon damage during BW. Weapon damage includes Elemental WSs so if you can brew on RDM and have someone else TH that would be best so you can nuke or WS during BW. With a RDM brewing you can safely do 4. With a THF if you get screwed on immunities a 4th could be risky. The immunities can complicate brewing multiple glavoids at the same time as well.

As for farming. A combination of AoE burning and actual NM killing works best. Burn for a couple hours or until everyone has adze/minochao KIs, since there is almost always competition for those NMs, and then kill what you have to to finish off sets.