I'm actually unaware of the process for the difficulty ratings - it may well be computer generated. Once we film the lesson, it's out of the instructor's hands.

So, just take them as a general idea of the difficulty, and realize that describing a song using a difficulty benchmark can be a bit subjective, and there may be some inconsistencies along the way.

Glad to hear the speed buttons are useful in this case!! Indeed, guitars such as the Ibanez and Jacksons are a little more built for speed - so would be a great choice for this type of music. That said, as far as advice for picking an instrument goes, you are doing the right thing by going to the shop and trying out a bunch of guitars. Everybody is different, so it's important to try different guitars to see what feels good and natural to you. Of course, you also want to plug in and see if it can give you the tones you're looking for.

Hope this helps!

Mike