Side View (need to put label on first picture):
Width: 757
Height: 350px

Top view:
Width: 757
Height: (2/3)*350

The preference is that input boxes are exactly where they should be on the image.
Ideally the image will be altered before arrows will be drawn.

If you start on angles, doing angles and sag inputs should be disabled.
If start on sag inputs, all angle inputs should be disabled.