Sexing a tortoise

[pacific chelonians]

A forum post from 2015 was recently recommended to me and it had this diagram on it I was wondering if this is accurate because Did not believe you can tell a difference between mature female and a proven female from the rest the tail

 

[wellington]

I think it's best too use it to sex male from female. Not proven or not or mature or not.
Not all males carry their tails to one side.