Hey man, i don't know if theres any way to calibrate a Xbox OG Madcatz light gun, i tried in some Games:
Dragón Gun
Zero Point
Deerhunt
Operation Wolf 1,2 and 3
Dead Angle
And all of them don't follow where i point.dont if i'm not doing something or Light Gun don't have support un this emulator.
Sorry for My Bad English, Anyway i'm from México if you need any light gun tester, i'll help you, i enjoy a Lot you're work on the OG Xbox. Greatings from México!!!