You can play around with the reserves minutes in order to make sure you get where you want to.
Keep in mind that in a walk out the starters always get 36, the backups either 10 or 5 and the reserves 2. The backups get 5 minutes if they are also selected as a starter and get 10 minutes if they are selected as backup (or backup+reserve) only.
The second game might be fine even without garbage time assuming p2, p3 and p4 are better or much better than whoever you select as starter for the game.