Thought I'd posted this but perhaps not; I made this a while back after Tessa made that comment. The breasts are scaled proportionally to be aligned with head/clavicle/shoulders/bellybutton/groin.
If Tessa had Leanne's boobs on her frame she would be approximately a 30NN/28O[UK], and make up 18-20% of her body weight and be comparable with [a certain Hooters waitress of the past]; incidentally Leanne's tits on her own frame are 12% of her body mass and Tessa's on her own frame are 7.2%.