I use Flash of Light for easier content, but Holy Light in case I need a big heal.
If I need a big and fast heal I use a macro:
#showtooltip
/castsequence reset=4 Holy Light, Divine Favor, Holy Shock, Holy Light
what it does is that the first Holy Light applies the Light's Grace talent, making it 2 seconds instead of 2.5 seconds. The Divine Favor + Holy Shock combo activates the Infusion of Light talent, therefore it has a 20% extra crit chance.
So the last Holy Light ends up being: 0.5 seconds faster AND have 20% extra crit chance!