The question is partly answered in the question about the rattle problem. When you only activate the Tremolo Switch when you want to go to drop tuning, you can set it so that it just touches the tremolo block very slightly, without moving it in any way. By doing so, the strings remain 100% in tune when you engage the Tremolo Switch. So you can tune down the low E string without having to retune all other strings. Well, to be honest, I still check the tuning of the whole guitar when I go to Drop D. But when set up correctly it’s very reliable. So going back and forth, even in between two songs, is definitely possible!