Originally Posted by timnz
I prefer to settle it by looking at the big matches at the big events
But doesn't your point here establish Wilander as number 1? Because as you said, he beat McEnroe at the French Open and the Australian - both tournaments that are more important than the Masters. Hence, Wilander won at the big events over McEnroe.
I would rank the masters over the Australian in terms of importance, considering the era-specific context.