No limit on the number of teams, although we limit players to only one team each. There are no playoffs or cuts; everyone plays all 36 points races. Over the years, we've had as few as 14 teams and as many as 30. My experience with different applications over the years is that the number of teams is only a pain for the commissioner / administrator during the sign-up / start-up period. After that, most software / web sites do the work.
Unofficial results are viewable live during the race. There is some delay after the stage cautions before the stage points are included, but they're usually added in within six or seven laps. Official results are usually up by Tuesday evening.
Driver selection for the next race opens Thursday mornings; that gives me time to update the groups based on the latest driver standings. Weekly results can be viewed throughout the season. The web site keeps track of how many times you used a driver. The only downside we've found to this application is that your team is automatically cleared out weekly; if you don't submit a new one, you have no drivers on your team.