Question about strategies and mineral scanner

[Asmala]

I'm new player and I haven't touched much in strategies or fleet formations (however I know arrowhead isn't good). So if I have a decent 30-40 ships fleet, armed with phased polaron beams or anti proton beams what's most effective tactic? Is there big difference in combat result between optimal, maximum, short and point blank weapons ranges? And what fleet formation is good? Or should I check everything at types that break formation?

And now the other question. Is there any point research mineral scanner or system mineral scanner when you can research robotoid factory under computers? Robotoid factory is cheaper to research, you get other useful components (master computer and computer virus) besides and it's the same facility for all the resource types.