Guest, MCP, I'm pretty sure that the method you describe is the one I use. When demonstrating the method, I stretch my picking arm out at shoulder height - with the back of the hand that holds the plec continuing in the same plane as the extended arm. The middle index finger joint is at right angle to the plane of the arm/hand. The finger joint that contains the finger nail, is at a 45% angle to the middle joint and the plec is placed against the side of this finger joint and the thumb placed on top. With the arm extended, the plec will point downwards.