Rear Meprolight Sight For CZ 75 SP01 9MM

[GBertolet]

I am looking for some information. I am helping my friend who has a SP01 that shoots 3-4 inches high at 25 yards, with 124 gr brass Blazer ammo. There is a #4 rear sight that came with the new gun. We are looking for a #3 to lower the POI. Neither one of us can find one. Only the #5 seems available. My understanding is the #5 will make the gun shoot even higher. I have tried contacting Meprolight , and so far no response. Does Meprolight even make a #3? If so, where can we get one?