You have more than one heavy? you lucky bastard.
I attacked that base last night; my squad was entirely wiped out three times in a row. I guess I need to research better weapons first.
Edit: It took me about nine goes. I kinda see where I was going wrong though - I thought increasing your team size was an unlock, and you'd be notified when you could add an extra soldier. Didn't realise you could just buy slots. Have been playing all this time with a team of four
In other news, this xcom is a pretty good game.