Most Helpful Girl
Most Helpful Guy
Ideally no for the sake of the girls' feelings unless they're kind of okay with casual sex, no strings attached -- you'll tend to compare those girls to your ex and they'll never be good enough because if you're not over her, she is what defines "best" to you.
That said, I can understand if you try anyway. It's miserable to come home to an empty bed when you're heartbroken.1