The Post Office Edinburgh and Leith Directory for 1911 shows Wilhelm in business at 6 Bruntsfield Place, Edinburgh
http://digital.nls.uk/directories/browse/pageturner.cfm?id=85923427 shows W. Kühn at 6 Bruntsfield Place, Edinburgh
If you go to the <a href="
http://www.nls.uk">National Library of Scotland</a> and go to their digital collections you will find the Edinburgh and Leith Post Office Directories in which you will find Wilhelm's home and business addresses listed for the various years 1893-1894 onwards. Click on
http://digital.nls.uk/directories/browse/pageturner.cfm?id=85165358 and in the "Search within" searchbox select from the dropdown menu
Scottish Post Office Directories and enter the search terms
edinburgh kuhn to see the volumes that such a search brings up. You can click on each volume (Jhg.) and find the relevant entry.
I was interested to see that in 1893/1894 Wilhelm was living at 75 Marchmont Road, Edinburgh (I lived at 60 Marchmont Road!) and also at that address was an M. Schnitzler, who, I learn from the 1895-1896 volume, was Mathias Schnitzler, printseller, picture frame maker, cleaner, liner, carver and gilder, importer of German gift mouldings, and artists' colourman, in business at 133 Lothian Road, Edinburgh.