2. I find the selection of extent is better done in 3, after opening the Selection Manager tool which is the second menu symbol.
3. The Selection Manager allows varied means of selection. For a rectangle, your 2nd click starts the drawing.
3. Then select the Stitch tab. The settings shown work well. Do select an appropriate folder for the resultant background image.
3. The image above is zoom level 20. Higher zoom levels significantly increase data volume as does selecting png rather than jpg.
7. If your map coordinate system is not Google Mercator (mine was GDA94/MGA94), then you need to select Transform so as to identify Google Mercator as the coordinate system of the Image.
Faced with the realisation that SASPlanet is not from a source known to me and also is delivered as an executable, I was rather nervous. OCAD’s endorsement was a promising start, soon diminished somewhat in finding SASPlanet wikipedia entry is in Russian. OSM’s wiki entry is brief. However, after a fair bit of searching I came to the conclusion that the risk is acceptable. The latest version is in BitBucket 17MB. Do please use Comments to let us know how useful it is to you.