"The most rational dividend philosophy would, I admit, be very unpopular: if there are opportunities to deploy the capital, or such opportunities are expected to come around soon enough, sit on it. If there is still excess cash beyond foreseeable opportunities, check the stock valuation. If it's high, pay a dividend. If it's low, stop the dividend and do buybacks. Alternate as required. This would be received more favourably if every dividend during high stock prices were called "special"."

I think this sums it up nicely. At what level of cash & treasuries in current conditions would it make more sense to do buybacks at the current price level or to pay a special dividend?

That number appears to be greater than the last reported level.