I agree that for this application the 2k Bamboo is too expensive and the 2k ume is a brick but more expensive as well.
So I've been working for almost a year on getting the 2k Speckled Ume added to the Nubatama line for just this reason.
I have a couple of them so far and Mark and I will be getting more in later when the next boat comes in.
I'm pretty certain it will be a big hit
Here's a picture of the stone.