Hi
how important ..i really dont know, i have heard that you will get same results if you use a twisted cabel.

advantages..their job is to avoid that the long cabels gets inteference that can give glitches.
but if you take a look on ailron cabels ...thier also long ...dont think it much diference there..

well i have used it !

god luck Kjell .
to save more weight if you dont already have done it you can use the new Schultze rx battery pack...ca 140gr with switch and reg ..2000Mah lipos