It may sound corny or cliché, it may sound like bad advice at first, but “fake it til you make it” is one of the core tennets of visualizing your success. Some guitarists like the level of control and consistency you get with amp simulators, but a little bit of wild energy in the room from a live amp can go a long way in terms of inspiring a great performance. For example, out of a real amp, when I palm mute power chords, I can hear (and feel) a lot more low-end rumble on the initial attack. The decision to use amp simulators instead of a real amp is up to you. Try both, and see which one gives you the tone you’re happy with.