Thank you Archie.
I wrote the seller a note and asked them to measure the window to see what width it is.
The Crown size is evidently 40.8mm US Eagle which is not the larger one I was looking for.
I'm starting to think I'm looking for something that doesn't exist. Big surprise. I do that a lot.
The octagon chips are about 48mm corner to corner and the largest 'coin' I have seen listed is 41mm

Here's a handy coin size chart:
http://www.jpscorner.com/coin-size-chart.html