I've always gone with a standard hour as it allows me to relax and get comfortable. I couldn't care less about the WG. Then, when I've had enough wine or whiskey, I'll get adventurous and take her when I want. I've had a two hour session, and admittedly it was one of my better ones. I didn't think she was going to fuck, but eventually once we were high and drunk enough we had a ball of a time.