Just as a FYI and you may already know about it but just like everything else in the world - there is an app for that. The app is called Count Circle. It uses the National Audubon Society’s CBC database which has 2,883 count circles. The app was last updated December 2018. You can also create your own count circle using the app.
I use the app when I’m getting near the edge of the circle to ensure I’m within the countable area. I am not endorsing the app nor am I trying to sell you on it and every other caveat along those lines. Just putting it out there as an option. I use it on an iOS system so I don’t know about androids.