Thetford Cloast Flange Seal

[arniland]

I have had my toilet out to look at the slide valve which I suspected was leaking down. Prior posts by ShrimpBurrito, Bill and others were most helpful. Thanks to all, especially Dave's Virtual Tour photos and explanation. Not sure what the issue was, but the valve looked good. After a thorough cleaning and reassembly with silicone lube, I'm ready to reinstall the toilet AND the old closet flange seal has been lost ($%^&$#!!). In an earlier post somewhere, Bill urged installing with a new seal anyway, so off to my local RV parts store. The only seal they have (marked for Thetford BTW) looks like it should set down into a closet flange that looks like a trumpet. My flange is concave. The old seal was shaped more like a donut. And, of course, the factory is presently closed closed, so I cannot call Ed and order one directly. Can anyone help me with a part number or the generic description of the closet seal I need? There cannot be THAT many different types of closet flanges! We are going on a trip in a little over a week and my lovely bride will not be happy without a toilet. Help!

Thanks in advance for any help or education about closet flange types.

Arn