Does the bottom line work with shooting say P51 rockets/F8 rockets at auto acks?
No. Frankly, trying to shoot down aircraft with air-to-ground rockets is like betting on the lottery for your income. I.e. stupid.
The WGr 21 rockets are canted upward, arc up and come back down (but the drop is much further than the up arc). You can even see the launch tubes are angled upwards. Further, while you only get 2 of them, the fixed range, fuse time, and predictable explosion points make it almost as good as 50/50 chances of scoring a disabling or killing shot on bombers.
Forget any delusions of using A2G rockets on planes, and forget using A2A against any fighters. They are meant for use against bombers for a reason. Bombers are LARGE targets and flying level in a straight line.
I've done the A2A bit before, got good enough to be pretty reliably accurate against bombers. Have a few films, have posted them and screenshots before (do a search, the threads may still be around). The problem recently is there are fewer bombers on when I'm able to fly.