Uhmm, I don't think there's a limit on how high someone could fly, I was asking for curiosity, though if she has frail build, I doubt she can fly as high as other people with better endurance due to the temperature and wind strength, dunno.

For the speed though...Um, well, you realize that charging would mean she won't be able to move as fast as she can, right? She practically might feel like she's standing still during charging. 

I take it the numbers next to names in the ability are how much Dust used for it? They also share Dust capacity, right?

Note: If she had next to no physical strength, I doubt trying to parry or bat flying projectiles is a good idea.