How does one use buoyancy? I'm not clear on what it's good for though being one of the highest level transmuter spells one would assume it's pretty powerful.

What does accelerate do? Compared to haste/quickening? When is it worth using (or not using) and what are the benefits of using it--and/or when should one not use it?

Lastly, malleability vs. corporeal hardening vs. petrify flesh. I'm pretty confused about which is best when. Is petrify flesh more of a spell to use against your enemy or to use yourself?