For storyboarding in Blender from what I’ve seen and heard most SB artist just draw the pieces(Background, character, props, etc) in front view and don’t worry about the camera until the end. Then they just scale everything down to fit the storyboard panel/camera. Now this is for Grease Pencil drawing. If you’re using 3D objects(Shaded or for tracing/rotoscoping) that’s a different story.
A better option instead of using the guide is to use Canvas. To turn on you go to the grease pencil overlays(To the right of the overlays) and check canvas. By default it is a 1 meter radius from the GP’s origin. So a 2 meter by 2 meter square. It is then divided into 4 one meter squares and those are then subdivided 4 times. That means each square is 1 quarter of a meter. Why the long winded description of the size? That is so you can understand the setting, which can be found in the properties editor in the GP/Data tab under viewport display panel you have the canvas subpanel. The color is well the color. The x and y scale is the Radius. So a 1 on X becomes 2 meters the diameter(Radius * 2). The offset adjust it’s position in relation to the origin point. The Subdivision is the number of cuts in each main 4 square(Each radius section divided by the subdivision). I can’t draw…YET…but people I know that can who use canvas usually just change the subdivisions to 5 or 10 depending on what they are drawing. then use offset if they need to adjust it position.
