These two different approaches are for different machines. Low inertia a/c, Light trainers etc should use power for rate of descent and attitude for speed method.
Higher inertia a/c should use point and power. In most light twins, either method works well, but as you are training somebody for an airline career, then get them used to point and power asap.
To be honest, either method works in light a/c though for little planes I personally teach the first one. There is no definative CAA guidance on this subject and I have never had any feedback to suggest using one over the other from any examiners or the Belgrano.
Be wary of anybody who advocates one technique over another without quantifying why other than "that's what the CAA want." There are very few areas where they have laid down exactly how we should teach a particular manoeouver.