In a rda or dripper you don't have to worry about dry hits due to over stuffing of cotton in your
juice flow area, like in rta's As long as your diligent in keeping your wicks with
juice any ratio should be fine. Sometimes when I just want to mess around and blow huge clouds I'll use 100% vg. I assume the guys in cloud comps use straight vg in there drippers as well. The choice is yours but I've noticed pg delivers better flavor then vg. So in short pg for flavor and throat hit. vg for clouds and smoothness.