The Sith eyes reveal works very well but I think the heroic music that plays throughout to the end of the fight might undercut the moment a little. Would it be possible to go with darker music? Maybe a hint of Anthem of Evil from TROS or the dark cave theme from TLJ?
I agree, the heroic music is a bit at odds with Rey turning to the Dark side and it should be darker music. This piece from Samual Kim might work at 2min mark as it’s good mix of heroic and dark. But I would understand if you think it’s becoming to fanedit-y