How do you describe an oval face without rigid rules?

[Miaor]

“Choose your face shape” is the opening instruction in a reader activity I am editing. At the moment, the descriptions for oval and oblong overlap enough to leave me unsure what to change. My revision needs to allow uncertainty instead of implying that one quick answer settles the matter. I have bookmarked oval vs oblong face shape as a comparison reference for the revision. Would you begin with a comparison of length and width rather than a list of labels? I can include an uncertain option, along with a reminder that these are broad descriptive labels. I would like the descriptions to stay neutral rather than rank the possible answers by appearance. We have room for a small diagram if the caption makes the intended comparison clear. Which part of the question would you revise before adding more possible answers?