Krusty, it's not that hard. Just get some alt on them, and vector correctly. I can't find it, but I made a chart of all bombers' level speeds overlaid, and the 25H has one alt where it's in the mix.
I've gotten a kill with every single 75mm hit I landed. A couple of times it took out one bomber and either set another on fire or tweaked it bad enough for the guy to bail out of #2, or just killed it. Hitting a formation flying off in auto-level from 1.5K is not hard with a bit of practice. 2K is probably doable reliably with enough practice.