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.
My glx in the process to swap 4g18 to 4g63t evo.... any brothers here got pics of the mounting at the timing belt side.... wat kind of mounting u guys use... cos 4g18 and 4g63 the lobang different... at least show me...