I'm going to discuss here the three previous points I mentioned and try to answer Pallymar with a little more Ulduar experience for myself.
I did Ignis 10, Council of Iron 10 and XT-002 25 this weekend, they are strongly different fights in term of healing. I think that one very interesting thing in Ulduar is that you have to be very adaptable, and change your healing startegy with each boss.
On the use of the Beacon of Light
Beacon of Light: The target becomes a Beacon of Light to all targets within a 40 yard radius. Any heals you cast on those targets will also heal the Beacon for 100% of the amount healed. Only one target can be the Beacon of Light at a time. Lasts 1 min.Simply said this skill duplicates all your heals to a specific target on which you have put your beacon.
Previous to Ulduar, I've already used it on the MT, or OT, depending on who I was assigned to heal and depending on the raid damage. If I expected to raid heal from time to time, it was on my main target (MT or OT). If raid damage was low enough to not need me, I'll put it on the MT or OT that was not my main target, to help its assigned healer.
The tip I got from the two guides I mentioned in my previous post was saying to use the Beacon on yourself, I found that change worth mentioning, as it was a strong change of style from pre-Ulduar. Pallymar disagreed with that tip, advocating a more classical use of the beacon (in the line of the ones I just talked about). I should say that, from my experience before Ulduar, that was really the thing to do ... now ...
In all my 3 boss fights (10 and 25 Man) I tried to use Beacon of Light differently, tried to see it's effectiveness, and how were other healers going. After several tries, I find putting it on you the most effective use, even though it'll make it generate about 60-80% overhealing ... (hopefully you are taking much less damade than the tank you are assigned to).
That defense of this strange and hps ineffective use could sound very weird to you, I don't doubt that. Please try it in Ulduar and tell me what you think of it. I'll illustrate why I think it's a good idea in a lot of fights with a few examples:
Ignis, if you ever end in the slag pot, you can continue to heal the MT without problem, and survive the pot, as you'll get a lot of heals on yourself with the beacon.
Iron Counsil, during most of this fight, raid damage is relatively low, and you won't have to think about it as a paladin, besides keeping your tank or off-tank up will be a challenge, burst damage in this three bosses encounter is extremely high, and triple chains of Holy Light are sometimes required. You should never untarget your tank, and having the beacon on yourself allows you to not bother about healing yourself, always be full life, and not die stupidly to an aoe burst (wether it is an arcane buble explosion or a green patch of death).
XT-002, this can depend on your assignment and your raid strategy, but once again, using the Beacon on yourself will guaranty that you're always full life, which prevents you from dying on unlucky damage procs, I have seen too many healers dying because they were mid-life when hit by a Light Bomb for example. An exception to that could be Tympanic Tantrum, if you need to raid heal (that depends on your raid) using the beacon on your assigned tank (probably the MT) could allow you to raid heal and keep him up at the same time. Though, take care, this is not Naxramass and if you happen to overheal on raid healing (overhealing is not duplicated by the beacon) that could mean his death, as XT-002 damage is not to be taken lightly.
To sum-up, it all depends on the fight, and I think that:
if your life is safe (considering the amount of raid damage in Ulduar that means that your raid healers are on their top),
if you can have a good target for your beacon, like healing two tanks at the same time,
then don't use the beacon on yourself.
In all other situations, use it for your own good, that will ensure two things:
you'll stay alive in most situations, which means you'll maintain the heals on your tank (a dead healer heals not much),
you'll keep your tank on target, which means faster reaction when these deadly damage bursts happen.
Sacred Shield is your MT friend
Sacred Shield: Each time the target takes damage they gain a Sacred Shield, absorbing 500 damage and increasing the paladin's chance to critically hit with Flash of Light by 50% for up to 6 sec. They cannot gain this effect more than once every 6 sec. Lasts 30 sec. This spell cannot be on more than one target at any one time.This spell was strongly nerfed in 3.1 with the addition of the last sentence. The reason was that "it was too strong" on a raid mitigation point of view. In fact, that was our real raid healign ability. So is it still worth it ? Oh yes, it is ! Keep it up at all times on your assigned target, or perhaps the MT if your target is not receiving constant damage (which would be a surprising assignment for a paladin).
Pallymar agrees with that statement. Considering Sacred Shield efficiency has not changed, and it scales very good with your spell power, keep it up at all times.
What should you do with this weapon in your hand ?
Judgement of Wisdom should be up on the raid boss at all time, with the mana regen nerfs (spirit, blessing of wisdom/mana tide totem) it is a clear statement. The only reason for it to not be up is that you're ponly having one paladin in the raid and Judgement of Light is prefered for that encounter.
So hitting the boss a few times with your weapon will give you a few mana procs, for free as you'll swing between your casts, without any sort of slow down on your casting.
Pallymar disagrees with that statement, saying that it is mostly worthless, and should not be necessary.
With a bit more raid experience, I would not say it is wortless. I was having real issues with mana on the Iron Council, keeping the off-tank (tanking the 2 "small" dwarves while the raid kills Ironbreaker) by myself. But if you need these mana procs, that probably means, as Pallymar says, that you or your raid is not up to the task.
I will add to that point that going up to melee can also be very dangerous, there are a lot of point blanck aoe damage, and the time you need to run to melee and run back to healing position can be too much as we mostly can't heal while moving.
To conclude on that, if you feel like you have the time, and don't really need to heal for a little, hit your Divine Plea and go melee for a little. As Pallymar mentioned XT-002 Tympanic Tantrum is a good example of such moments. But whenever you are not sure of the situation, stay far from aoe damage and don't take any risk for so little mana regen.
I'll try to put more healing advices here when I'll have more Ulduar experience and perhaps some boss healing guides. Thanks to Pallymar for adding some good insight to my previous post.