wireing??

[Ellis]

You can use the same thickness wire all over which is what many do for convenience, it's just you want to make sure the main current handling wires (so anything between battery and the distribution to different ESCs) will comfortably handle the draw. Often that means you save some weight by using two sizes.

If it's a rambot you could probably get away with 18awg for everything. Others who have built similar bots can confirm/disprove that.