keybinding for macOS Sierra

As it needs 3 keys on a German keyboard (alt shift 7) to get a backslash, I would like to use the keys on the numerical keyboard to get this character (and others difficult to obtain as é). I tried two different versions of ~/Library/Keybindings/DefaultKeyBinding.dict available at http://alexanderstoffel.selfip.org/KeyBindings/DefaultKeyBinding1.dict and http://alexanderstoffel.selfip.org/KeyBindings/DefaultKeyBinding2.dict After rebooting, the first version has the effect that hitting the corresponding keys does neither insert the former nor the desired character but the acoustic system alert is audible. The second version does not have any effect. How can I get the desired effect? I am using a MacBook Air with macOS Sierra (10.12.1) and with an additional Apple Keyboard (Product-ID: 0x0250).

I haven't had much luck the keybinding dict route, seems very spotty what works and what doesn't. Far easier to use an app like Ukulele to make a tweaked keyboard layout exactly how you want it - no issues whatsoever. Much recommended.