Yeppers,
I whole heartedly agree that the size of the hen seems to influence the size of her eggs. But, quite frankly, I have a Production RIR that lays dang near every day, but it is a medium sized egg.
A second production RIR lays a large egg almost every day.
My EE on the other hand lays a large to extra large egg about 4/7 days. Early on I remember her as the chief thief of the three, as she could steal something out of the RIR's beaks faster than a blink of an eye.
All of these birds were hatched in march.
So which is the better "layer" pullet?
It gets back to what your goals for your flock are! Is production more important than size OR DOES SIZE matter? And don't get me wrong, your flock goals can change as well. Mine did.