after seeing yours you made im thinking maybe im looking at it wrong, or backwards with the 3d printing on idea. i was thinking of just printing the end plastic section. maybe it would be an easy setup to take the simple pre bent lever and set in a mold and pour the plastic around it you could then easily carve away the plastic to shape and drill the rivet hole and end for the ball bearing to sit. that way you can have the lever all the way through and be solid. also you could easily get the notch in as to not need to cut the cover. now im thinking i may have to give it a shot just to see the process from what my vision is.
@elroberds what year is your donor handle off?