Thank you so much, that helped.
What I was tripping over was page 38's assertion that EXEC had a mini-layer or dynamic key mapping capabilities. The example they gave seemed to indicate that you could code on the fly state sampled key layering. I read this to mean an alternative to IOUMD. In essence, that any switch "state" could be used, surgically, as a layer.
This is the example they gave...I just tried to adapt it, unsuccessfully
MapKey(&Throttle, APPAT, EXEC("MapKey(&Throttle, APENG, L_ALT+'6');"));
MapKey(&Throttle, APAH, EXEC("MapKey(&Throttle, APENG, L_ALT+'2');"));
MapKey(&Throttle, APALT, EXEC("MapKey(&Throttle, APENG, L_ALT+'4');"));
Anyway, I'm using Aussiedroids outstanding Elite Dangerous target script which already had shifts setup, so i just added
//David Start
MapKeyUMD(&Joystick,H4U,
DX15, //UP Layer
DX15, //MIDDLE Layer
DX28 //DOWN Layer
);
MapKeyUMD(&Joystick,H4D,
DX17, //UP Layer
DX17, //MIDDLE Layer
DX30 //DOWN Layer
);
//David Stop
Works GREAT, THANK YOU!