On the VPI JWM unipivot arms, from your baseline setting, the VTF increases as the stylus height increases. The VTF decreases as the stylus height is lowered. This is presuming the VTA is the same.
Another way to look at it, from your baseline setting, if you have VTA tower, as you increase the height of your VTA tower you lower the VTF. If you decrease the height of the VTA tower then you increase the VTF.
Another way to look at it, if you want precisely the same VTF on 120 gram, 180 gram, and 200 gram records, then you would need to set the baseline for 120 gram, then increase the height of your VTA tower to compensate for the additional record thickness.
From memory, the differences are slight, something around 0.03 grams or so, from 120 to 180 gram.
Another way to look at it, from your baseline setting, if you have VTA tower, as you increase the height of your VTA tower you lower the VTF. If you decrease the height of the VTA tower then you increase the VTF.
Another way to look at it, if you want precisely the same VTF on 120 gram, 180 gram, and 200 gram records, then you would need to set the baseline for 120 gram, then increase the height of your VTA tower to compensate for the additional record thickness.
From memory, the differences are slight, something around 0.03 grams or so, from 120 to 180 gram.