I recommend flying a mustang in AH, as it's the plane we seem to be talking about here in example, level and just above ground level, then at 2k, then at 5k then at 10, 15 and even 20k just to make the point. The higher the altitude you fly above the ground/earth, the lower said horizon of said ground/earthenly object will apear, relative to you. Then, I want you to particularly note about where the horizon sits, from your visual perspective, to your wing at ~7k. Nose down to 30-degrees AoA, wings level, and look out to your horizon. Is it parallel to where a guage would be on yor canopy, or if you had lines drawn on the same wing your now pretending to see clearly through to see the edge of the horizon?
Proper terminoligy would be glide bombing I believe, as with dive bombing you're directly or nearly directly above the target.
And the lines, on canopy or wing would rarely "line-up" unless you had pre-calculated precisely and taken into account your height/line of sight (which even for the most consistent of pilots would change rather drasticly depending if you had just or are about to repack your parachute, mission clothing, etc..) and also consistently came in at the same altitude to your target every time, what you're doing is observing, at an offset, a paralleling line to the horizon.
Also, keep in mind, these were aids for experienced/trained/practiced pilots, not novices simpley thrown into the pit (which is arguabley most of us AH players). Achieving a 0, 45 or 90 degree angle, or acuratley assesing you were at such a rudimentry angle, isn't nearly as hard as 30, 50, 60 or 25 that these guys were trying to achieve or at least acuratley observe to then compensate. (in particular, shallow angled dives).
I must honestly admit though (unless you're the jolly green giant, sitting ontop a fresh packed chute, crusing at a mystical 120k when initiating your shallow-angle dive), the the first few imediate lines, closest to the fuselage, I can only imagine them as being useful if you were comming in a steep-banked dive and had a wing high against the horizon or are more likely purely asthestic.
Also, don't forget we have the fortune in AH of always having clear skies and unlimited visibility. Finding the horizon, clearly, is easy and can be seen out to a far distance. Add some cloud/weather though in AH, and you fly/maneuver more off instruments than visual references/ques.
