Expression: "His height is a little less than mine."

[Tom]

Hi

I know that a typical expression would be:

[Yankee]

Hi Tom

At the risk of getting certain people on this forum all worked up (again) because I've dared to comment on whether something sounds 'natural' or not, here is my opinion:

Your second sentence would sound awkward and unnatural unless you had some kind of very special contextual justification for wording it that way.
.

[Molly]

Sounds unnatural to me also, Yankee. Go say it!