Does anybody know of a single word which describes a method or mechanism which is more reliable in getting the best answer (to a question which has no "correct" answers) or provides better results than the status quo?
In the business, industrial and emergency services world, the concept of "best practices" is used to denote what is best under the circumstances rather than having a "one size fits all" rule or process. It takes into account the means, ability, experience that is available in a real world situation and is constantly being evaluated and updated based on personal experience and new information. Not a single word but it communicates the concept that you are describing.
I would simply describe such a method as "preferred."
"Preferred" implies that the method or mechanism being described is more effective and accurate than an inferior method or mechanism.
Edit: If you are looking for a noun which denotes a "preferred method," I am unable to help.