Rules Questions

[prj]

If V has a once-boosted Fireball (2 copies of the shtick in play) - after using it, does he flip both copies or just one? Meaning could he use a boosted version, and then have a "regular" version left to use before resting?

Right, only one flips per battle. The rulebook gives an example of this with Durkon using Thor's Lightning on page 22.