This is all very fine and jolly, but in the real world of regular touring aeroplanes there is a need to "fly the numbers" I watch people fly some of these machines and it makes me cringe. The key to most aircraft is to know the sensible power settings and speeds for each phase of flight as well as attitude. Then if you have some combination of rev counter, manifold pressure and air speed indicator and attitude indicator (which can be the picture out of windscreen) you can fly the thing accurately in take off, climb, descent and approach.