For me the key parts of the report were
Structural deficits of the scale of Scotland’s, and particularly Wales’ and Northern Ireland’s, would not be sustainable on an ongoing basis.
“They would need to be tackled by some combination of spending cuts and/or tax rises, in the absence of a rapid increase in economic growth post-independence, which is probably unlikely.
“Indeed, recent research suggests disruptions to and increases in the cost of trade would likely adversely affect the economy, at least in the short-to-medium term.”
David Phillips, an associate director at the IFS, said Scotland’s on-paper deficit “reflects significantly higher levels of public spending per capita in Scotland”.
“The higher levels of public spending are in effect paid for by fiscal transfers from the South of England.”
The IFS said that “none of this means that Scotland cannot afford to be independent, nor that there aren’t a range of opportunities for better policy to improve performance and better address Scottish needs and preferences”.
But it warned: “Saying you are going to boost economic performance through better policy making is, of course, easier than designing and implementing the necessary policies."
I don't know how much of a bigger flag can be raised which highlights the fact that in the short to medium term (aka the next 10 years) the economy would be hit hard and there would cuts and tax rises required!