When you look at the General properties of a DB, there are 2 items, Size and Space Available; does space available refer to the actual space that is available out of the total from the Size? this is not the total actual space available in the whole drive, is it?
No, that's just the amount you have used within the disk already allocated to the database. If you have a big chunk of available space and you "shrink" the database, you'll see that the total size will drop dramatically in step with available space. Size will grow again as needed.