Sorry, I thought you were using lightgun, but of course you can also use e.g. xbox pad. First, start the pad so that it can be seen by the operating system. Then run the program DemulShooter_GUI.exe (page selection: P1 configuration) as P1 device select "MC Xbox BT gamepad", configure buttons if necessary, save config. In the "page selection" select "elevator action invasion" use Patch, if you haven't done it yet, here you will also see which keys to insert a coin or start the game, or change them - save - done. U can still use same script - I just checked, it's not very convenient, but it works. I guess it's better to play with the mouse, but whatever... Good luck.
If you are using the monitor in tate mode, you don't need to change anything (in "GameUserSettings.ini"), U may need these changes on horizontal oriented monitor. As for the script itself, just copy it, paste it into notepad, save it under a convenient name but with the ".ahk" extension - if you don't have it yet, install AutoHotkey to use it.