You can collect 6 wedges altogether per one session. You need to earn more points for each wedge unlocked.For the 5-Round:
However, you need to earn less points for the 3-Round so it may be faster to get wedges.For the 3-Round:
If you get all 6 wedges in each session, you will only need to play 5 sessions. Hope that helps. Any updates or comments, let me know. Have fun!