Victor got back to me with an enormous 13000x9000 pixel drawing of the motor including the details of the output shaft. When I took the motor to the machinist I offered to get details of the spline but he wasn't very interested, saying that splines are usually modified from the standards to meet the particular application. I'll call him up tomorrow anyway.
The drawings also help with the adapter plate design since they include all the measurements needed to center the motor.
Interestingly the drawings are dated 1997 and 1998. You think you might be doing something new but really you're retracing steps taken 10 years ago.