Honestly, just start twisting knobs, see what happens.
That footage is really damaged, however, so I'm not sure how much the BVP4+ can improve on it. What I see is a video with destroyed mid tones, severely damaged chroma, obliterates highlights, no true darks. That's common from 8mm film footage transferred to VHS by playing it on a wall backdrop/screen, and using a VHS camera to shoot it. That's not much better than how modern movie pirates take a camera phone and shoot the theatre screen. It just looks really bad, almost not worth watching.