In my experience there is no length that answers that question. Obviously the longer you are, the greater chance you have of hitting the end of the cul de saq on more women, but all women - just like all men are different.
For example, my ex wife was about 5’6” and 130 pounds. There were many positions we couldn’t have sex in because it hurt her. She could only fit about half my dick in her mouth before gagging so my 7.5 inches of BPEL was more than enough.
My current wife is 5’ 100 pounds and is just a tiny little thing. She can take every inch I can give her and in my opinion would enjoy about an inch more. During blow jobs, she can press her lips to my abs and swallow 7.5 inches of dick like it’s nothing. She has absolutely zero gag reflex, which I love!
Moral is - my dick is the same and provides two very different results for two ladies.
When I was first with my new wife, I thought I was going to tear her in half. It just wasn’t the case.
Lucky for me, I’m the first guy she has ever been with sexually so she doesn’t know what an extra inch would be like.
This is very interesting, it really seems the smaller the girl the bigger the pussy. Some very small girls have enormous pussy.