You can't have too much Int. Stack it.
From the EJ Holy Paladin forum:
Intellect has received a HUGE boost with WotLK mechanics, and is now the best stat for Holy Paladins by far. Let me list what 100 Intellect gives you:
* 126.5 Intellect, with BoK and Divine Intellect
* 1897 Mana at the start of the fight
* 39.5mp5 from Divine Plea, if its used on CD.
* 21.3mp5 from Replenishment, with 90% uptime.
* 4.7mp5 from Arcane Torrent, if you are a Blood Elf.
* 25.3 Spell Power
* 0.759% Spell Crit
This gives you a lot of mana, which lets you cast a lot more Holy Lights and be more liberal in using them. If you stack this stat you will be able to spam Holy Light during most fights.
So back to your question. You're specced Prot. Someone could probably do the math to figure what stats you would have if specced Holy, but I'm not sure it would be a productive use of time. To heal heroics I think you need a minimum of 1400 SP and that would require an empathetic tank and lots of cc. The best shorthand way to do it would be to stack Int while you shoot for 1400 SP.
And don't worry about not wearing plate. At one point I was in Naxx with six pieces of mostly mail and some leather, and the rest plate. The mail and leather I was seeing had better stats than the plate I was seeing. Go for the best stats. At one point I even had a blue in the leg slot that was kilt - took a lot of ribbing for wearing a dress.
____________________________
"the people can always be brought to the bidding of the leaders. That is easy. All you have to do is tell them they are being attacked and denounce the pacifists for lack of patriotism and exposing the country to danger. It works the same way in any country."
Hermann Goering, April 1946.