The pro's don't dive at 0 G to deliver ords. If you're in freefall you have no control over the impact point. You also accelerate too quickly at 0 G even with your engine off. A consistent dive angle in the range of 45-60 degrees will generally give the best results.
In a dive you are at G<1 anyway. The steeper it is the closer you are to 0G, so the difference in acceleration is insignificant.
You dont aim the bombs while in 0G - you check your aim point. The fact that the future impact point does not change is the whole point (pun intended). It gives you a second to estimate it, without it changing all the time. You also dont need to hold 0G for more than a second. Looks good? release, no? correct, go into 0G again. What happens to many players is that they start from 12k or so, dive and then correct, not sure, correct, not sure, correct, not sure... oops about to crach, release in panic, miss, hit the ground. 0G gives a very intuitive feeling to where you will hit, without any aids. As a result, the player is confident in releasing from a higher altitude. It teaches you to get it right in the first or second guess, instead of walking the fuzzy future impact point along the ground, loosing altitude while you wait for it to reach the target. The latter is great if you have a CCIP computer and a HUD. We don't.
Of course, a real pro can release the bomb while in a 6G spiral dive, looking back, typing profanity on channel 200, and still hit the target.