Voltage, Amps, and Heat

[z1nonly]

I have some questions that I hope you guys can help me with.

I've read that running more voltage helps with decreasing heat and increasing runtimes. Since the motor doesn't draw much amps, it will generate less heat.

Which set-up would be more ideal for less heat and more runtime:

Set-up A:
-4s 6000mah
-higher kv motor
-gearing to match battery and motor set-up

Set-up B:
-6s 4000mah
-lower kv motor
-gearing to match battery and motor set-up


I also read that with more voltage, there would be more cogging; hard to start off or run at slow speeds. Is this true?