Guys with experience can chime in but 4.10 DBW with some extra mods is probably your best bet for consistent nightfighting.
BAT is great, too, but not so much from a bombers perspective as I don't know if anyone will find and attack you.
AI in 4.10 doesn't have the realistic visibility restrictions so can see you regardless of darkness, clouds, etc.
This sounds bad, but in anything 4.12 or up (try a qmb for 1 am) the AI can't find or attack bombers*
*but In BAT 4.2.1, poltava's battle over Berlin JU88 campaign, I did see a AI 110G-4 anf a 190A-8 attack bombers. Don't know of that was a one-in a million thing, something with that plane, mission conditions, or a c&c object. Looking through the C&c manual I didn't see anything like that.
One thing that is a bit of an immersion breaker is anything with Schrage musik fires both upward and forward guns at the same time, sending tracer nowhere and giving them away. From what I read, an older version of the SAS engine mod had it working correctly. There is provision for the ai to carry out such attacks, maybe one of our code experts can chime in, or someone has that working version in their archive somewhere.
Was a minute since I dug into this but I can scrounge up some links if you are interested.