Two tanks, one beacon, lots of splash

Big heals is a tank healer.  It's the role most expected from people with spell power plate.   The Beacon of Light allows for raid healing when there's a single tank taking damage, but several encounters require two (or more) tanks to be taking damage at the same time.  Depending on the number of melee in your raid, the Glyph of Holy Light can be splashtastic.  Beacon a tank, drop continuous Holy Lights on the other tank, and watch the Glyph splash heals to the melee.  It is very similar the Shaman's Chain heal.  A shaman will start the Chain Heal on a tank and keep all the melee topped off.  This splash is significant and should be respected by the raid.  As Big Healers we need encourage players to stay grouped together when possible.  Planting a Holy Light on a player at range can splash too if they aren't all spread out.  On fights where the raid takes continuous damage, this splash damage will often be a significant chunk of the effective Big Heals.