FWIW, I called the shop. I had emailed and got no response. After getting the pipe, I thought I might buy a spare larger bowl and one of the old meerschaum bowls. I got a nice guy on the phone who said they have nothing to sell for the Kirstens right now. They are wanting to get the factory back up again, and they have nothing in stock. I asked if he could tell me how to figure out the size bowl on my current pipe, and he said he couldn't really. There was just too much variety.
He said I could call back in a couple of months.