Whist the AC gives good general advice; it is not a great example for how many details there should be in an SOP. The AC lists all of the subjects that should be covered by procedures, thus by following the advice an operator includes everything, but the details are still his choice to some extent. In my experience this AC can be mis-used; the local regulator uses it as a template for everything that has to be written down so that he is confident that the operator is doing a good job, but with little consideration as to the effectiveness of the procedures in-flight. Similarly the FAA HQ required tightening of ‘in house’ regulatory guidance after an accident when it was discovered that they and local inspectors were unaware of the manufacturer’s changes to operating procedures in icing conditions.
Para 9 a (2) ‘The procedure is practical to use’ probably offers the best advice.