I was curious about the auto fire option, does it go off of how close your base is to the biters or is it random what it will fire on?

it will shoot at spawners and stuff, like artillery targeting

Sometimes its a bit wasteful, as it aims on small basses, while there is a big base next door?

I'm not sure if this is right, but it seems like it fires to the spawner closest to the silo? (sometimes that is not what you want if your silo is relative close to the edge of your base (instead of in the middle)).

Perhaps there could be an option to work like that ion cannon mod, it will only auto fire if a radar detects something..?

I don't control any of the targeting logic, and I don't plan to change the way it works