Addendum
Just to stress I am not diminishing the importance of flying blue line before someone jumps down my throat
If you have the discipline, courage and accuracy of flying to peg blue line good for you! but that means on hot days, or at grosse, or on windy turbulent days being able to accept minimal or no climb or maybe even a descent rate of 500 fpm.
My problem with blue line is that in low powered twins the margins for error are small. Add in panicking pax and other distractions and it's only too easy to loose blue and to get into a mess!
In the right conditions and weight blue line may be the right way but there are other ways with larger margins for different situations.
For me flying light twins is about respecting the limitations of a light twin and flying out of the box considering a number of options and using them even if that's closed throttles into s field.
Remember too that a light twin will fly quite happily all day on one engine if your flying level and use that fact to your advantage !!
Pace