Multiple DK spec advice - BG's mainly

I'm levelling a 2 DK, 2 Ret Pally, enhancement shaman team. (Weird I know).

I'll probably be leading with a Ret and having the DK's as followers.
I'm sort of confused as to which spec to run the DK's as. (they are currently 58).

I'm leaning towards blood for the self healing, but was wondering if this is the right choice.
Would a frost build (added survivabilty) or an Unholy build be more suitable?

Is there a spec and priority rotation I can run that shouldn't struggle with runes and runic power.
I'll probably create a /click set of macros (and of course will post them here).

Is there a spec that fits with the pallies better?

I'm new to the melee multiboxing and want to keep things simple for now.

I like the unholy build, but have not taken a death knight far.

www.talentchic.com is a decent site.
It will list the most common specs (via armory scans) for each tree.
You can check for pvp, pve, raids etc.
You can also check based on where your gear is from.
They have the most popular glyphs and enchants as well.

Not claiming the popular choice is the strongest, but when a lot of people spec one way, its probably not a horrid choice either.

Personally I would spec one deep blood for glyphed heart strike and aboms might and the other deep frost for Icy tallons+chillblains+hungering cold.

Though another solid options imo would be going blood/frost hybrid on one for both aboms might + icy talons and full unholy with the second for ebon plague bringer, perma ghoul (leap+stun), and AMZ

Brilliant - thanks for the responses. I'll definitely check out talentchic.

I may actually end up with a 3 DK two Ret team to simplify things.