Kalata
Out of the Silent Planet
Aquarius is perfect for this spot, but its first half (it will have its good nights) and then Book Of Thel's high parts are some of the most difficult songs for Bruce to sing live. And some of his best. Love them. Nice alternation with the vocals for the latter. He can swap it with Tears Of The Dragon to be earlier in the set. Is the pre-chorus of Road To Hell easier? Not really, but it's shorter. Laughing In The Hiding Bush and The Magician can have extended crowd participation.
Darkside is becoming more and more of a strugglefest. I think Bruce should replace it with Jerusalem if it becomes too much. Love the song, but considering how many options they have...
Other songs like Jerusalem, Kill Devil Hill, Omega, A Tyranny Of Souls, Power Of The Sun, Back From The Edge, Silver Wings (the previous song is The Alchemist) can also work great there - main set closer.