I don't know, I kind of like the second one. ;)

You could make a entire gag out of Vader's voice being tweaked until they get it right. If you can create a closeup of the main medical droid, and add goofy sound fx of him adjusting the voice, that would sell it. Might also give Vader a new motivation to crush all the droids in the room.

I am aware of voice changing gizmos that the more elaborate Vader costumers use, but have no idea of the quality or price.

I agree the first one is the best the more I listen to it.