Could you clarify a bit further what you mean by having to set up your ruler between machines? Ruler settings in documents are a part of the document itself—just as much as the text is—so they really shouldn’t be changing between sessions or computers. Do you mean the default Scrivener ruler settings? If so, you should follow the instructions here, which will help keep both computer’s Scrivener settings completely synchronised.
Also, you might wish to read this advisory.