"Where would it have left the Scots, if there had been a Yes vote recently?"
Exactly where they are now! If the 'Yes' campaign had won, there was no plan for actual independence to kick in for at least another two years...ie Scotland would have been part of the UK until the "divorce settlement" was finalised.
Given the fluctuating nature of oil prices - about which everyone in Scotland was fully aware - the price of crude oil may well have rocketed by then. Who knows?
In addition, the prospect of further oil finds are now likely in the North Atlantic, nothing to do with the North Sea, which was the only area ever mentioned at the time of the referendum. The Atlantic area would, of course, have been unavailable to England/Rump UK, as they have no contiguous shoreline with it.
And, as has been mentioned above re whisky, Scotland was not likely to be solely dependent on oil, anyway. For Pete's sake, if Malta, Denmark and so forth can exist independently, whyever would Scotland have been unable to do so?