Wouldn't say easy with 30 watts, but around 15 - 20 should work fine with 50 - 70 VG since the One doesn't really have that much of an wicking material and the feederholes aren't that big either.
Might work with 30 watts if you take primerpuffs and don't chainvape, but since the airhole isn't that big the vapour gets quite hot.
So in short, you're iStick is more than enough for the 1 ohm heads.
Sent from my iPhone using Tapatalk