Usually, my friends and I queue after 4 PM. 5PM to 7PM seems to be pretty poppy in terms of ranked, but I don't know if that's always. Yesterday was the launch day for the Season so I can't say if the queueing will stay on schedule.
Sometimes people just need to be asked if they want to do team ranked, and they'll assemble their group. You can whisper me if I'm on, and I could try to form one to queue against ya.