The rule is.......There are no rules.......You need to try some and see what works for you.
Just last week in Santa Barbara(Refugio),I ran into a guy riding a gel seat.....TURNED AROUND BACKWARDS!!!!.....I thought it was an anti-theft device.....NOPE!....
I am now cured of that horrid feeling.......I will NEVER question anybody about saddle choices again.....EVER!