The only thing I've noticed about the 'jumbo sized" west coast, rhizomes, is a tendency to "split". The top of the rhizome gets a split down the middle, over the winter.....which I suspect is do to freezing. I have 'lost" a couple of them....I guess pathogens can enter into the rhizome easier if it's 'damaged'......but, as was pointed out....those biggies have so many increases started, that the loss of "mom" isn't too big a deal.
I know the last several orders from Schreiners were large rhizomes, but definitely not 'wet'....they were VERY dried out, so, somewhere there is a "happy medium", I suppose.