What Holysack said. It's not that the healing was low or anything, because it wasn't. It is just with that much mana left I feel I can do a lot more then what I did. Getting into the habit of pushing that envelope to where you are using most of your mana as a holy paladin is what seperates the men from the boys.
Take Tortos for example, with the amount of spirit I have, I can afford to overheal a bunch before a stomp to put mastery bubbles across the raid, if I wasn't using the Eternal flame method. It equivilates to less damage being taken, and leads to you being higher on the charts.
Same thing goes for Qon, overheal before Unleashed Flame, and before Fist Smash. When everyone is stacked, just use the AoE rotation. Of course, only do this if you have the regen to afford it. If not, use a more Eternal Flame approach.
Even tho we run with 2, and sometimes 3 priests in our raids (We run 25m), they spirit shell before that stomp and end up topping the chart because of it. We can do the same thing to some extent.
Rampage, Static Shock, Caustic Gas, Quills, Lightning Storm, that method works on all those mechanics. Pre-AoE healing on Melee works wonders.
With all that spirit, don't ever catch yourself just standing there, even if the raid isin't taking damage during that global, because the raid will be taking damage at some point in the future, might as well bubble them up.
I'm typing too much. I'm sorry. TL:DR, --> IF <- you have a bunch of extra mana regen, throw out some overhealing to put more mastery bubbles up. Become good at that, along with actually healing damage, and you'll see what I'm talking about.
P.S. This is coming from a 25m standpoint, not so sure this would work so well in 10m unless everyone is within 10 yards of each other at points were you don't have to be spread. This method doesn't work on a fight like Twins.