I think Alexander the Great would work best as the first encore song to play rather than the show opener. Just imagine the band having walked off stage, lights go off, fans are chanting "Maiden! Maiden! Maiden!" and then after a few minutes of that, you hear it. The howling of the wind. Hardcore fans would know, casual fans and everyone else would be curious. Then a voice comes over the PA: "My son, ask for thyself another kingdom. For that which I leave is too small for thee."
Proceeded by the first 1:40 of the song being played, in the dark, over the PA. And then the band and lights burst back on at the 1:40 part of the song and play what no one dare dream they would ever play.
I think the place would go fucking nuts, probably one of the biggest pops a band could ever get from a crowd. Shame that it may never happen.