Agreed. Unless the pickups are very, very different from one another, the difference is very small. I recently tracked an EP and did a shootout between a Duncan Distortion and EMG 81. Surprisingly small difference and again, was more in feel than tone. The Distortion felt more aggressive, while the 81 was more rounded off. Thought the Distortion sounded better in isolation but the 81 sounded better in the mix. It's still worth it to shootout pickups prior to tracking because that 5% is enough to pay attention to, but it isn't going to be a massive difference in the high-gain realm.