So someone told me if you stretch your penis as far as you can and measure it, that length will be around the same depth you can achieve? well i tried and got to about 7 but that was without stretching it fully i could tell there was more skin to move (so sorry for being crude) but i need reasurance i will get a decent vagina by dr phillip thomas ?

the "stretch test" is only good for a plain inversion, if you're having a scrotal graft (which most surgeons do these days) then it may be more or less depending on how materials are used.

also the area measured depends on if circumcised, and does not extend to the pubic area because that has to be "extended" down to the top of the clitoral hooding.