if you're wanting  to change your Point of Impact we will need to know what your guns POI is now, so that we
can make the necessary adjustments to the new rib. If your not sure how high you would like your rib, we suggest
trying some Balsa wood from any hobby store, buy a couple sticks in different heights, tape to your barrel
(I use black electrical tape)  and mount your gun a few times with each size stick to see what works best for you.
You could even get pins used in sewing with the little white heads, cut one off leaving enough pin part to push
into the balsa and you have a bead go out and shoot a round and see how it feels and looks.
If you're not sure where to start we can make Suggestions to get you going.