Tyrant Rave
Banned
Okay, I tried it. Doesn't really work against bosses, though. Since when you lock-on, Lady doesn't move her reticle.
Against bosses I like to use shotgun and rockets. Shotgun can charge while running and jumping and all that so it's pretty easy to get a charge off during a fight. From there you can enemy step off of them while blasting them away or use fireworks for a lot of damage.
You need to be a bit more careful with rockets but they break some bosses pretty hard. You just need to be a bit more careful when you choose to charge. If you have an opening for a level 3 rocket it will rack up ridiculous amounts of style points.
On regular mobs and enemies it's pretty easy to get SSS combos with the handguns if you're mixing up charge shots with her other moves. On beefier enemies just use shotgun and just blast them point blank and you can get up to at least an S from that alone.