Tanking - Needing advice (GLD)

[Pinch]

I have a question regarding the early dungeon boss fights.
I have only tried Sastasha and Tam Tara.

When tanking on the bosses at the end and the extra mobs start to spawn, are tanks expected to run around and gather enmity on the adds or concentrate on the boss and let the DD's sort the adds out?

You should swap to everything to help deal damage. The only time you wouldn't do this is if the mob you were tanking had an un-telegraphed frontal AoE, which I don't believe happens in the early levels.

If the mobs are something that last more than a few seconds, you should probably do a flash or two and maybe some single target enmity generation, just so your healer doesn't get smacked around.