There are two types of well-endowed tgirls: those who are, and those who claim they are. Many escorts on Eros and elsewhere either lie about their size or think that measuring from the anus to the tip is the way to measure a cock (wrong; it's along the top, from the abdomen to the tip). There's an old adage that tgirls on Eros add 3" to their length.
However, that's a disserviced to those who truly are well-endowed (Vicki, Yasmin, Mia, Danielle, and many others) and who advertise truthfully (if they advertize that is). I daresay that, while the percentage of tgirls who are over 7" is smaller than advertised, the percentage is nonetheless greater than is typical for men: that is, you will find a higher percentage (maybe even 5%) who are over 8", when in the general population that figure is closer to 1%.
By the same token, I think (though no scientific studies have been conducted, despite my own random samplings, lol) that there's a higher percentage of tgirls who are below normal in length (< 5") as well, and maybe an even higher percentage than is above normal. It is an interesting distribution. Who's up for some thorough sampling and analysis?