Need Filmholders for 9x12 KW Patent Etui

Just took delivery of a backpacker's dream - 9x12 Patent Etui. However, the filmholders that came with it won't fit. Two of them bear the KODAK name and the other is a no name. They appear to have identical dimensions to the Zeiss 665/7 and to several Certo holders which I also own. Indeed, the new holders fit perfectly into my 9x12 Certotrop. Meanwhile I'm dead in the water with the Patent Etui. What kind of holders am I looking for and where's the bestplace to look?

You're looking for unmarked ones that just barely won't fit in most other 9x12cm plate cameras and are just a little bit shorter than the other ones. That's bit of a problem, since it's difficult to identify them from a picture.

The best place to look? I'll have a look in my box of surplus plate holders, and let you know if I have some!

I found them, I have four available. PM me.