For base model Vios with rear drum brakes, the manual gives the exact dimension (0.6mm clearance) for the shoe adjuster. It also includes the diagram for the "one-way" star wheel orientation.
However, even the legendary "Indestructible" Toyota requires regular maintenance. Guessing when to change the oil or ignoring that subtle engine knock is a fast track to costly repairs. This is where the becomes your most valuable asset. vios service manual