Everything is going to totally depend on what you are flying. I hunt GV's in attack mode all the time in a variety of planes. In the F6F-5 I like to start 10K over the target (you can see their dots on the ground at that alt), dive at 45-50 degrees at full throttle with my pipper dead on the target and drop at ~1K, then pull out (gently enough not to break a wing).
On the other hand, in a JU-87 you don't want to be over ~6.5K for a full power dive at the same angle, and depending on the size of the bomb, you may have to keep the pipper aimed just past the target.
The faster (and lower) you are when you drop the more accurate you will be.
At 45 degrees your bomb will still arm at ~500 feet. The 800' requirement is total distance travelled, both vertically and horizontally, so don't drop so early that your not aligned properly.
When hunting Flaks, I like to start higher and drop anywhere from 3-6K. This keeps me out of their effective guns range.