@MysticZap: You get GuitarHero the Chatot. First and foremost, a musician must be both musically and physically apt, so it must have one physical move and at least one sound-based move and use one of them at least once every time it is sent out. Now, its system is based off of a "Rock Meter" that starts at 50%. It can increase or lower depending on what it does, its zenith being at 100% and its nadir being at 0%. Here is what it can do:
Hit a note - Every time it hits an opponent with a sound-based move, its Rock Meter goes up by 1%.
Miss a note: Every time it misses with a sound-based move, its Rock Meter goes down by 2%.
Hit a section - Every time it soloes a trained Pokémon with only sound moves, its Rock Meter goes up by 10%. Stacks with "Hit a note" and "Miss a note."
Miss a section - Every time it faints during such a solo, its Rock Meter goes down by 20%. Stacks with "Hit a note" but not "Miss a note."
FC a solo - Every time it soloes a GLP, its Rock Meter goes up by 50%.
Miss a solo - If it faints in the process, its Rock Meter goes down by 50%.
FC an entire song - Every time it soloes a gym leader, its Rock Meter stays at 100% for the next two Trainer battles.
Fail a song - If it fails to solo a gym leader, its Rock Meter goes straight down to 0%.
Moving on, the Rock Meter actually determines your BP limit, which is listed on this chart:
0%: 49 (except Hidden Power)
1%-33%; 60 (except Hidden Power)
34%-66%: 80
67%-99%: 90
100%: no limit
One more thing: unless its Rock Meter is at 0%, it can always use "Star Power" (Fly), though usage is risky. Therefore, flip a coin every time you attempt to use it. If heads, Star Power went off without a hitch and you can use Fly without any drawbacks. If tails, you must sacrifice 25% of your Rock Meter before activating it.
Questions/concerns?