Along time ago I received TB rhizomes with NO foliage about the size of a dime and placed into a paper bag with name on that shipping was SOOOOOOOOOOOOOOOOOOOOOO HIGHHHHHHHHHHHHHHHHHHHH you would have died. This was a trade and I sent what I send to my customers and he tried to tell me they were in the worlds worse with total mildew and rot as he opened the box. The kept me from trading for years. As you can figure they were the tiny new rhizomes that had not even developed yet...and yes, I have never traded with him again and he is no longer in business.
I really do not have a problem with size, as there are some iris that the rhizome NEVER get big no matter whether east or west coast. I want nice fresh dug iris that shows the seller or trader cares.
When digging I make the cut for the biggest there as what we plant back is the small ones as they will grow nice and big over the winter.
The east coast and west coast iris are so different in size. That does NOT matter they both grow.
D