It would be good to crop your images. They are seriously distorted in this forum.
As for using saved sketches, you want to be sure that they are "self sufficient" with the exception of one x and one y reference. When you open such a sketch, you have the option to set a scale. When you place such a sketch, it also attempts to snap to an X and Y reference if it is near the drag center.
Make sure your sketch is fully constrained to itself and use locked dimensions.