Seeing as how this is a request to change a coin's page, I am going to have to reject this request solely because it is impossible to complete. Right now, all we have is one diameter, regardless of the coin's shape.
With that being said, if you could re-post this thread as a 'Suggestion for Numista' in this forum:
https://en.numista.com/forum/forum15.html, that would be excellent. I, personally, think this would be a great feature (if implemented); however, it must first be posted under the correct section so the suggestion can be properly tracked.
And of course, if the feature is implemented, your coin (whichever one you are talking about), can be changed, as can any of similar shapes.
EDIT:
Oh, but you can always request to add this information to the comments section. That way, the information is still on the page somewhere.