I have been healing on my pally. To be honest, it was mostly PVP, but then I have no idea why I decided to heal some heroics.
Proof I was healing! See the little plus sign!
Pain and suffering. We wiped on a couple of bosses, mainly because I was an idiot, like the eye balls – I got stunned and died. Then on Jaina when we had an extra pack and then on Murozond…he was horribly hard.
I think we wiped about 4 times over 3 instances, so considering it was my first time not too bad?
I was having massive massive mana issues, once I get that sorted out it may be ok.
I then decided (insanely) to do an LFR as healer, with my Frosties. It was a horrific LFR, we wiped on trash and Morchok because of an idiot, but it went smoothly after that once we booted them out. I healed, badly, but I healed.
Overall I was most impressed that I was actually healing the twilight heroics. I didn’t think I could do it. I really didn’t. I guess the week of PVP healing really does help 
I, too, have only really healed at ‘max level’ in PVP (level 80). Sure, I did a few dungeons, but not many. Wintergrasp was fun to heal because you could have 50 ppl in range for crazy heal spams all around. I’ve also healed low level dungeons, but that tends to be a bit simpler, in some ways. Kudos to you for having fun and healing! I may have to write about this soon, too.