Guild Wars 2

My brother is looking for a Guardian build for WvW. We play in a 20ish people team focusing objective and we often come accross HUGE zergs.

I thought a tanky Consecration build would be good but I really have no knowledge of the profession. I know many Guardians use heavy prec/tough build with might on crit and selfheal on boons + 3 Shouts.

How btw would a Cleric geared Guardian impact a 20man group when heals only affect 5 people?

I saw this yesterday and tried it with a Zerg last night, It was really good.