Re: Calculating angle of shot.
Have you worked up the Amax load fully (at distance, playing with OAL, etc)? Sounds like you may have a load that's passable on paper at the short lines, but not really solid as you go out.
The 168 Amax's, if you find a speed and OAL your rifle likes should shoot inside the 168 SMK's at 1000 any day.
I agree that 175/178s would be the way to go. Just how often and how regular were the 1047 hits on a 10X10 plate with 168 BTHP's?