+1. Those two focal lengths feel quite natural to me as well.
I am not sure where the 10mm figure, for focal length is coming from. It seems to me that we do not normally experience the foreground stretching, in daily life, that occurs with such a short focal length. I would say that, for me, 24mm or 25mm is about as wide as we can go before the picture starts to look unnatural. Sure, many of us have and use lenses wider than that; and sure, the pictures can be spectacular; but I think that in viewing such a picture, we realize that we ourselves don't really see that way. It's not that our peripheral vision doesn't cover a view that wide; it is more (I suppose) that anything very far out in the periphery is perhaps not included in our subjective perception of what we see.
I do think the phenomenology of vision as we perceive it, has got to be more useful in determining what is the "natural" focal length, than measurements of an eyeball, etc. Thus while an ophthalmologist may tell us (and they have) that the focal length of the eye is X number of mm, that doesn't really tell us what we experience. Only we can know that!