It is very true to say that if you play with a light touch then you have much more room to get louder, and can employ an huge range of dynamics within your playing. To me, this philosophy would make lighter strings the choice if you want to play with a lighter touch. What I was thinking while practicing today though, it that lighter strings can cope with much less. If you really dig in, they kind of fart out. For you, what's the optimum gauge/tension of string that allows you to comfortable play with a light touch as well as can take it once you start to really hammer the strings?