Maybe we look at the ratio of country perimeter to area? Counting the number of exclaves could also be a factor. And maybe a ratio of the distance to cover all the exclaves divided by their area?
So if a country were a perfect circle it’s perimeter to area ratio would be 2/r, it has zero exclaves and then it’s width would be the diameter.
If a country were two perfect circles of the same diameter, separated by a distance of the same diameter, it’s area ratio would be 2/r, exclaves would be one, and it’s width would be three times it’s diameter.
So now you can imagine a country like Chile, modeled as a really skinny rectangle, has a pretty large perimeter to area ratio, no exclaves, and a width roughly the length of the rectangle.
I guess you’d have to decide if archipelago nations are measured as the geometry of the sea they own, or as discrete islands.