so i bought the ijust2 from eleaf at the mini vape meet at sir vape in durban and its awesome but one thing iv noticed is that you need to have spare coils incase one fries on you well you out, however i am finding that trying to find the .5ohm coils for the ijust2 is becoming difficult to find which leads to my question what are the best alternative commercial coils to use for the ijust2?