This isn't some super secret exact ratio. You're using a harsh (to the molds) solution to scrape down the surface and kill off the flora. The only rule of thumb I would follow is if you exceed 10% acidity in the vinegar, limit the contact time to ~5 minutes, else it will start eating away at the cheese too much. Beyond that, use whatever vinegar you want, and as much salt as you want. Generally, people saturate ethanolic (store white distilled) vinegar with salt and use that.
In terms of what you do, you scrub off the mold until gone. Make it look like new. This is like stripping paint off a door, trying to get it back to original shape.