How to determine who is in playoffs?

We have 3 divisions with 4 teams in each. We use to have only 2 weeks of playoffs with the top team from each division going in and 1 wild cars. However this year we want to go to 6 teams with 3 weeks of playoffs, but don’t know what 6 teams to let in. Should we do the top 2 teams from each division or the top team from each division and 3 wild cards spots?

In our league - division winners make the playoffs and the wildcard teams are determined by most “total points for”. That way, you reward the teams that managed their teams week-in and week-out the best.