oh yeah man team obj has always been my fav since halo 2. I love team games,especially CTF, bomb or territories on Valhalla.
Skulls didn't take me long as i used a guider for 4 of em.
I have all but the one which requires you to be boarded by someone then board them back within 10 seconds. I keep trying to make people board my ghost as i ram it into a wall so they have to reverse a bit. But either they don't bother boarding and kill me or the pause until i can board them back is long enough for them to escape.
lol, hit me up man and I'll help you with it....its 'cheating' i guess, but it worked for me and one of my friends lol....twas the only one i did that for. And ya, that one on the Ark was a lil' homo =/ heh