The Ruler Guide is available as an option to turn on in the Layout and Message Builder Tool Advanced Control Panel

To turn Ruler Guides on or off:

• In the Builder Tool, select the Advanced Tab
• Once on the Advanced Tab you will be able to click the ruler icon

  

• This will turn on a ruler at the top and far left of the canvas are

Once the Ruler is turned on, you can drag guide lines onto the canvas from the top or the far left of the canvas

• While dragging a guide line it will show the location of the line based on canvas percentage (or in pixels for a fixed size design)
  
  • If you hold the shift key while dragging it will move in 1% increments

The lines will disappear when the ruler icon is clicked again, or the design is saved