Not much thought has been given to altitude. I occasionally find bomber formations well above 20k, sometimes above 25k. For these, the 190A-8 is not a good choice. Why? because it is a slow climber at those heights and accelerates poorly. If you're not already at altitude, forget the 190A-8 and consider a 109 with gondolas.
There's many aircraft that are good for dealing with bombers. I like the P-47s. While the D-40 offers the best climb at low to medium altitude, I prefer the N model for higher buffs due to its tremendous speed. Eight .50s will flame any bomber with one pass. Plus, it has offers a far greater ammo load than the P-51D.
I also like the F4U-1C for buffs up to 25k. Good speed, durable, top tier firepower, lot's of ammunition.
For low to mid altitude bombers, anything with multiple cannons, or one very large cannon is adequate.
However, as has been mentioned, poor tactics will offset the best fighter.
My regards,
Widewing