Think there might be something your friends assertion Deeranged but there has never been an explanation how the deficit can be overcome. GERS figures are supposed to show the size of the deficit but the nationalists dispute the validity of the calculation. I can't remember the name of the report that made clear the oil revenues were enough to make Scotland a wealthy nation. It was done to deprive the Nationalist movement of this fact that made independence a prosperous probability, possibly even a certainty.
Oil prospects have plummeted and so the additional tax revenues are not available. I think that Andrew Wilson's report was very disappointing for the economic case for independence. In fairness to him he has retained his credibility by creating a realistic report which is to be praised.
I don't know why the independence economists can't produce a convincing case, so I am still in the doubting side of the discussion.