The answer was no. Simply because it's detailed enough for you doesn't enter into it.
Unless you're prepared to say that those folks paying one dollar more is fair, then we have to have a number.
And note: Buffett didn't say they should pay more. He said the rates should be raised. These are two completely different concepts. You could raise the rates and have people move their money in such a way as to not pay any more at all. From Buffett's position, simply talking about rates, this would be an acceptable outcome.
I think we're at a spot where we can agree to disagree. Whether or not rich folks owe their fair share or not is a meaningless conversation unless and until you can actually start describing what you mean by "fair share." Without those details, it's just political feel-good bullshit, sadly. I expected more from Buffett.
I tell my wife, "You know what, it's not fair that Bill pays so much all the time. I should pay more."
My wife then says, "Your argument is confusing, and what's more, it's feel-good bullshit. You didn't give me a specific number on how many dollars you'd want to pay. Would you pay with a credit card? Traveler's Cheque? Based on total after tip or before?"
The supposition between reasonable people should be that I pay some reasonable amount more than I have been paying, but I don't go over the top and foot the entire bill. Is it fair to ask how much more I'd be paying? Of course, and the final justification of just how fair the arrangement is would depend on that number, as you've said. However, it's perfectly reasonable to say someone should be paying more, and have a discussion on that topic, without having to go deep into the specifics of how much more.
He said that a rich individuals' total tax burden, by percentage of all income, should be brought more in line with what the middle class pays. I am reasonably sure you're being purposefully obtuse here. The only way for a person to "move their money in such a way as to not pay any more at all", and still meet Buffett's criteria is to make less money, on purpose.