This is the biggest issue for using our eggs. Using a scale is the most accurate way to use our eggs. (it is also the best way to bake.) If I'm just using a box mix, I take a few middle sized eggs. If I only have huge and tiny, I take one of each (as lone as it calls for two eggs). If it only calls for one egg and I have to choose between huge and tiny, I choose huge. I've learned over time to eyeball which eggs will work together well. I'm not typically "on the nose" with the weights, but I doubt that if I went with supermarket eggs and weighed them I would be too. I actually never weighed my eggs until I had my own chickens and started getting such a variety of sizes.

I always use mine for baking and know that in a recipe an egg (without its shell) is 50g. If I need a white only, it is 30g. A yolk only is 20g.