The top-left corner of the subPanel uses the same coords as the top-left corner of your saved sub VI. Also the "subPanel document size" will be the same size as your running VI. I.E. the sub VI's should have the same placement / appearance as "regular" VIs, or exsiting in a subPanel.
If you want to make sure they match up, then save your sub VIs with the origin at the top-left (0,0). One way to do this is to place a property node on your block diagram, right click the header to change the property class to "VI" and then select "origin" property, right click to change to write. Right click again to create a cluster (0,0). When you run your VI, the top-left will align perfectly with the two thick lines. Save your VI so that the VI will open at this coord (even in the subPanel). -David
