When drawing the coordinates is in an .OSM file the result it is stretched horizontally. Things are a bit wider than they should be. Does this have something to do with the globe projection?
What scale do I have to reduce the horizontal values by to get things looking right?
You’re probably editing in EPSG:4326 (latlong) mode, and the rendered maps are shown in Spherical Mercator (900913). You’ll need to switch your editor* over to get rid of that ‘stretchiness’.
Which editor are you using there? JOSM or Merkaartor?