Never use your hand. The simple reason is that ALL the garage door manufacturers and the garage door association and the CPSC
use and publish the 2x4 method. When you go to court they will ask you why you didn’t use the prescribed method. I have tested many a garage door with the 2x4 method. Often they do not reverse. Simply turning the 2x4 on edge will in most cases cause reversal. Haven’t lost a door yet. The problems occur when the door is not properly inspected BEFORE operation.