I've been looking at the G-spot of the female character Mona from the Genshin impact game created in China by the multi-million dollar company hoyoverse.
I started studying the structure in what took about 10 minutes by searching for rules png pulled from Google
And seeing that Mona's dress is very tight to the body (this can be seen when seeing that the navel is visible to the naked eye) Mona has a G-spot that is 2cm high and a width of about 1.8cm
Add that the average depth of a woman is 8cm plus the fact that she can stretch
Basically, to please this lady you would need about 10 cm
With 15 you can hurt her and with around 20 you can kill her.