My tribe is extremely similar to Mystwalker's tribe except my youngest was a female.

21 male
19 female
18 female
17 female
6 female.

None nursing as I wanted all to be able to work. It's worked out very well so far. I put the male with the oldest female after the village was fairly well established and eventually got a male child. Then I put my oldest male (now 24) with the next oldest female and she's carrying a baby. Then I "accidentally" ended up with my third oldest female carrying a baby too when I set her to parenting and had her "telling a story" to the two kids. When she finished, she got together with my 24 year old male before I could stop her, lol!

I've had a couple different ones get sick, but were easy to "heal" and have not had any "negative" events yet, so things are going smoothly.

Edited to add: I would have LOVED to have even one runner, but never saw a single one offered, lol!