After the exciting news about the 24, I wish I could show you more progress in my home workshop, but this is all I can post here right now.
I noticed that something was missing on one of the 36's corner seats.
But it's not hard to fix. Just have to make sure the springs seat properly into the new crosspiece.
And in not-quite-diner news, our friend Ron Smolen sent me this link to a page about a Birney being used as a gas station office in Springfield, Missouri. There are some interesting comments as you scroll down. It's not quite clear whether it was used for serving food, but it's close.