Stealthy has a decent tanking DK click sequence in the wiki.
It is linked from the Macro/Click sticky in the macro forum.

I'd look into getting the hunters and the DK onto a one button click.
Then spam a single key, gets you decent tanking and dps.
Then you just need to worry about positioning plus heals.
And spamming at a consistent speed.

Checking the movie forum is a decent idea.
You can see how a few different boxers have done instances.
That gives you an idea on how to do things.

Most seem to quest for levels.
And then instance for gear, once you reach maximum level.
But quite a few do instances at the intended level.. so they should be doable.
Your composition has a lot of AoE power.
And can single target burn things down too.
You'll have Bloodlust/Heroism, and strong totem support besides.



Post Script: Stargate rocks.. SG-1, Atlantis or Universe?