There is a HUGE generalization as to egg size for a breed and as all generalizations are, is not a good indicator of what a specific bird might lay. My 2 Faverolles are supposed to lay USDA Medium (51g to 57g). On a REALLY GOOD day they might make the very low end of that. The average size (of all eggs ever laid) is about 46 grams.
My 4 Y/O EE (from Ideal) has an average of 64 g, the VERY TOP of Large and that is brought down by her pullet eggs. She rarely lays anything under 70g now and is frequently laying 72 and 74g eggs - Jumbo. She is currently laying 2 eggs every 3 days or so.
The 3 EEs (from Meyer) that will be 1 year old next month have an average size of 58, 57 and 51g. Now that they are past "pullet egg" age, they are running about 60, 64 and 52g so solidly Large, XL and Medium. The one that lays the Medium eggs is a machine, 85% of the days since her first egg and as of yesterday is on a 14 day streak; 10 days or more straight is normal for her. And yes, I do know that will change after first moult this fall.