If you increase the valve pressure (turn in the screw), you increase the valve's resistance to opening at lower vacuum levels, meaning part throttle or at idle but you also increase the occurrence of compressor surge, which is what a BOV is there to prevent in the first place.
Recent visit to friend's tyre shop saw a new brand of budget tyres. Land Golden from Thailand. Currently got 2 models. One Symmetric model LG17 and one directional model LG27.