Keep in mind for screen shots that all of the other NPCs, especially the monsters, are massive. So if you set the height slider all of the way down, your character will look about 4 foot tall once you put them onscreen.
CoH made it hard to make child characters. My main character originally was going to be younger (because child-sized invulnerability tank = cute and funny) but CoH's boob slider didn't quite go down far enough so the youngest I could make her look, in the clothing pieces I had at the time and wanted to wear, was a mature 12. I have a character in my "waiting to play when the game comes back pile"that is a Carnie of Light who looks younger with different costuming (I used the toga from the Valentine's Day event).
For the actual scales, I started with the "normal person" setting, put the chest all of the way down, waist all of the way up, and shortened the legs a little more. From there I had to be careful to keep the arms and hands at least partially covered too- CoH character's are all pretty buff. Otherwise you get the horror of Baby New Year's arms...