The answer to this one is the 3 piece handle, similar to how you'd do a 3 pc coffin box style handle. If the curvature were not as pronounced, I'd use a clevis pin/hinge, drill straight in from ricasso end of things, then angle drill from butt end. On this one the three piece handle will give me an accent material where a full tang would normally be. If I didn't want a three piece I could do a 2 piece and mark the tang on one side, mill out an exact fit for the curved tang at half the thickness of the tang and then do the same on the other side for a perfect fit over the curved tang.
Hope I made sense of that.