I just levelled this toon to 90 on Friday evening. I picked up enough gear to get into the LFR's other than ToT. I knew that my healing numbers would be poor, and my mana efficiency would be less than stellar. I wasn't completely wrong. My numbers were respectable for my gear level going into things, but my experience raid healing left me short on mana early in the fight.
Having not enough mana to heal, I decided to start hitting the boss to get my seal of insight procs, and I had an epiphany.
I set up my bars with judgement, crusader strike, a targetoftarget holy shock, holy prism and light-of-dawn. This is kind of my "questing" set of bars, which of course, I never use because I don't quest as holy, but I had it there in the background.
I found that using the inexpensive attacks to build holy power allowed me very liberal use of Light-of-dawn, coupled with beacon, battle healer glyph, holy shock and seal of insight, my healing numbers in LFR went UP 10K, and my mana reserves became infinite.
While I am very aware that this is a situational use of skills and talents I found that playing this way was FUN, as well as effective. Every heal is a smart heal, so overhealing was minimal. Every button is an instant, so I was unaffected by movement. Seal of insight healing is free, and when the seal procs actually has a net mana return! Coupled with EF on the tank this setup ruled.
Given the inherent mana efficiency of this build, I am considering trying again tonight reforging all spirit to mastery/crit for improved throughput and see if I can still maintain the longevity.
Alternate method of play? Certainly not as a 10 man main healer, but for LFR it's a blast.
Just thought I'd share.