The Guardian poll anounced that Darling had won the debate but the other part of the poll was of the undecided voters who 76% Salmond 24% Darling. It's the undecided who matter now and that was a clear victory for YES.
The currency question is political because Better Together know perfectly well that there is no definintive answer to this question until AFTER the Referrendum. THAT'S WHY THEY KEEP ASKING IT. Salmond has no choice but to keep saying what he does because that is his political position. He actually told everybody where they can find Plan B, C, D, E, and F. In the white paper, listen again! But he is not going to outline it because that is what Darling wants so that he can ask another load of irrelevant questions that do not have an answer.
Personally I don't worry about the currencey because Scotland will have one with little problem, it is a red herring. The real question is where is the UK heading with it's huge debt. Privatising the NHS, Lowest pensions in Europe, Low wage rates, Foodbanks, Tuition Fees. There is no doubt in my mind that the UK is in terminal decline, Scotland has a chance to escape all this and build a good future, it need to take this chance.