I find the key to healing succesfully is to make sure your dps and tank don't need attention. 1 button macro for tanking and dps leaves you free to focus on healing or movement. I play with 1 resto shammy and I have a bunch of different heals bound to heal each party member. Having a g11 keyboard with the extra macro keys is good for this. Don't forget on that second gundrak boss that the quicker u move from those purple spots the less damage you need to heal. I usually don't heal at all in that phase. Just nuke it down and move as neccesary. Heal up in collosus phase with heal self key on all chars. Hope this helps

edit: using bloodlust and fire elementals on elemental boss phase will also help. On my first kill my pala solo'd the last 25% and my pala was quite undergeared then.