Spacers will help you roll out the paste evenly.

You can use: 
  • Lollipop sticks (1.5 mm)
  • Candy floss sticks (4 mm)
  • Toffee apple sticks (5 mm)

 
You can also stack the lollipop sticks on top of each other:
  • 2 sticks = 2 x 1.5 mm = 3 mm
  • 3 sticks = 3 x 1.5. mm = 4.5 mm
  • 4 sticks = 4 x 1.5 = 6 mm
  • 5 sticks = 5 x 1.5 = 7.5 mm
and so on :)