Thanks very much for your reply and help Retro808, I should have added that I'd already tried the controller mapping functions in both LB and BB but found they only worked for about 50% of the emulators I'm using. For example, even if a controller button combo does initiate shutdown of Citra, a pop up box always asks if I want to shut down the game and I need to press 'y' on the keyboard and I'm trying to have a setup that only uses a controller without the need of a keyboard. In addition, I can't seem to get either Dolphin or Cemu to close at all using controller mapped buttons in either LB/BB? Finally, some emulators don't open full-screen (even though I have already set them up individually) and using a controller button combo is really useful to initiate that.
So, with these issues in mind, I decided to write AHK scripts and had success at first with D-input but not X-input as described above. However, there is a good chance I'm not using the controller mapping function properly (as I'm quite new to LB/BB) but, so far as I can see, I believe I'm doing everything correctly?