Paul,
Have you thought of Running your Stainz back to back as well. In Bosnia They had Duplex Locomotives in the early days of the 76mm Gauge. Effectively these were Stainz Locomotives with very few modifications. Pictures of them are quite rare, well in Duplex mode but many survived as singles for many years. This link is a simple drawing of what they looked like.
http://www.angelfire.com/co3/drustvo/Cira/173crtez.jpg
Have you made a YouTube Vid of your Sachen Pair? If not would you consider one please?
JonD