Thanks for posting your comparisons. One follow up that would also be great is who sent you what you ordered. One of the most important things for me in this process is getting the correct root/plant. I'd rather buy directly from the grower too, knowing I can go back to them directly if I have a problem. Size can depend on recent growing conditions also, I know in the midwest portions had drought conditions to a severity for a couple of years.These conditions, just like any farmer/grower can effect your product.
Another thing to look at would be, did size translate into blooming the first year? It is supposed to, but I'd be curious about that. Since you have a lot documented here, follow up would be interesting and much appreciated.
Thanks for your information. I have my favorite growers and will pay a little more to buy from them. I more often go for a specific peony I am looking for then choose a favorite farmer. I also participate in our peony society auction in the fall and obtain favorites (and more rare) peonies that way.