Just because an egg is large or mis-shapen doesn't mean it will be a double yolker.
I had a white Australorp that laid 90gram eggs routinely.
Never produced a double.
Other than candling the egg, there is no way to tell until you break it open.
Large & double yolkers are usually laid by hens in their final egg laying years.
We've had quite a few large eggs, but no double yolkers as yet. When hens start to lay, they tend to lay smaller eggs, then as time goes by the eggs get larger.