New group: Paladin + Shaman - how many of each?

Now that my 5x paladin group is almost at the cap and thus able to farm up some heirlooms, I'm looking at leveling up some other classes so that I can mix and match groups to be able to handle the most possible content.

One of the things that I'm wondering is - if I have a group mixed between paladins and shapeople, how many of each is optimal?

With 1P 4S I have Sanctuary on the Paladin, Kings on the Shapeople, shadow protection aura and all other resist types are covered except for arcane. Is this the optimal configuration, or would there be a benefit to another Paladin?

Can a good argument for a second paladin be made?

I've also been thinking of a 1DK + 4S group - in that case I think an argument could be made to drop one of the Shapeople and put in a Retadin, to get blessings and the aura.

Any advice?

I would go:

1x Prot. Paladin.
3x Elem. Shaman.
1x (Any Spec) Warlock or Bal. Druid or Elem. Shaman.

Three (elemental spec) shammies, can heal all five-man content in a Pally/Shammy group.
The Warlock gets you 13% spell power, via Curse of the Elements.
The Druid gets you the same, but until Cataclysm gives you something extra to manage (Eclipse procs).
The fourth shammy, gets you more totems and the same rotation across all your toons.

My main PvE team is 3x Elemental, 1x Protection and 1x Warlock (Demo).




A 2nd pally would be Ret probably.
That basically gets you Judgement of Light and Judgement of Wisdom.
You will have Sanctuary/Kings plus Might/Wisdom on the team... meaning every shammy can drop Healing Stream instead of Mana Spring.

You'll have to deal with IWT/CTM, melee range on bosses etc.
Which isn't a big deal, just something to be aware of.

The Pally, with an all caster team, is easy mode for a lot of content.
I wouldn't trade a shammy or the lock for a second pally... but in a melee team, two pallies is a good choice.