I do not have exact measurements at the moment, but I am seeking advice for making this gasket for a Water Inlet Valve on a Conti Prestina. This gasket is making me very nervous, as I am pretty confident these kits are now extinct. I would really like to find a resolution without having to buy too many expensive tools to make my own. Thank you all for any help.

Excellent Idea! I am embarrassed I hadnt thought of it. I will research further.

I opted to create this seal by making a mold from the original, using an epoxy putty, which turned out surprisingly well. Now I can make a new seal with a food grade high temp silicone.