oval coins

How would you put the diameter of oval coins. do you put the diameter of top to bottom and then side to side like 20x15 mm or other way

Thanks in advance

A quick glance at what's been done so far says one of 3 choices:

1. left/right X top/bottom
2. top/bottom X left/right
3. no dimensions

Edit: found a new one:
4. single diameter (anyone's guess which way it goes)

To be honest most oval coins are not oval but elliptic and I would put the largest diameter (the height) in the features and the height width in the comment.