I'm going to a audio show to test headphones, and I need a list of music that will cover the low to high frequencies. Since I will only have a short time with each headphone, I will need music tracks that maximize my time with each headphones. I also need to test stuff like soundstage and imaging, so keep that in mind when making suggestions.
No offence meant but I think you're over thinking this, personally.
I think It's best to stick with music you know and play regularly when testing gear out from my experience.Then you'll notice the differences more (from familiarity) going from headphone to headphone.
One of my main test tracks is Voodoo Chile (The long version). Why? Because I've been listening to that song for 41 years, I feel like it's ingrained in my DNA and I notice even subtle differences when testing equipment because it's so familiar to me.
The other thing that may happen is that you end up buying a pair of headphones that sounded great during your tests but doesn't really have the sound signature you want for the type of music you listen to. I've been burned like that before.