Determine the POI with your ammo of choice
Determine the actual POA with the ammo of your choice
Calculate the difference between these two points
Refer to the "sight calculator" feature on Dawson Precision's website. Be certain to include the distance at which you are measuring POI and POA.
This will help you determine what height front sight you need for your bullet to strike at your desired POI.
Cruise various websites (Dawson, CZ Custom, Cajun Gun Works, Trijicon, Ameriglo, etc.) to find a sight of the proper height and desired width that will fit your pistol