Yes, the more the merrier. The first few of my tribes I couldn't sustain because I was spreading them too thin. So I decided to have the tribe work on one task at a time. Currently, my tribe is doing extremely well.

When the crops are ready for harvest everyone joins in (I reward them with a group swim), they raze a building together and research together.

Since my tribe is growing I have begun to leave half researching and the other half doing the other task at hand.

It appears things are going much faster, my food supply is well over 2,000 at all times.

I love my little people.