Dave don't worry about the long post it gives people a lot to work on. As I recall the HW35 was not well suited to a telescopic sight. If you look at the guns profile you will notice a decided droop from the cylinder to the barrel. This was a design feature, God knows why, but unless you use a particular type of scope mount your '35 will always shoot low. The open sights are mounted on the barrel its self therefore are aligned with that rather than the cylinder and will shoot accurately. do not be tempted to over power the gun it was designed around the 7 joule power limitation in Germany and is not suited to go much higher, I had a certain affection for these but they are a Marmite gun.
Drink good English Bitter beer and shoot safe,
Micky Spillane