I raid as a resto druid.
This is what I would do for a CC Healbot.
For Tank healing:
Rejuv and then three stack LB.
Refresh Rejuv and LB until tank gets to about 85%.
Spam Nourish (which will keep LB refreshed now) and refresh Rejuv when it drops.
If tank gets to about 60% cast HT (this means Nourish/Rejuv/LB cant sustain the tank....switch to bigger heal).
Switch back to Nourish if above 85%
If still not above 85% after three Healing Touch cast tree form
Regrowth
Healing Touch
Make sure you hit Swiftmend on CD if below 90% (swiftmend is cheap)
For Party/Raid healing 1-2 people dmg:
Cast Rejuv if 1-2 ppl take dmg.
If below 60% cast Nourish (if rejuved already) or swiftmend if not on CD
For party/raid healing 3+ people dmg:
Cast Wild Growth
Cast rejuv
If 3+people are below 40% cast Tranquility
If Tranquility is on CD:
Cast Treeform and cast regrowth on each person
Cast rejuve on each person
Cast LB on each person
Cast nourish on each person
Thats pretty much all I can think of right now.
Edit: About thorns. I usually never use it (huge mana hog) unless there are multiple mobs. I wouldnt worry about putting it into the CC at this time.