I don't think Metamagic's approach is suitable here.
Depends on what you take from it.
Basicaly Metamagic are just toggle buttons that alterns your outcome calculations ...
Basicaly Battlemaster Manouvers are just toggle buttons that alterns your outcome calculations.
And same goes for Sneak Attack.
The point of Metamagic is that you can apply multiple effects to a single spell. I don't think you can perform multiple different manoeuvres within the scope of a single attack.
As far as i know, there is only some exceptions that can be used while you are allready using different metamagic ... otherwise rules say that you can only use one.
And toggle one, while using another ... would not be so different from combining Sneak Attack (ranged), or Battlemaster Manouver (ranged) with Elemental Arrow.
