A silly question maybe, but when filling cartomisers with a mix of two e-liquids, do they need to be pre-mixed, or can you just drip-feed say 5 drops of each until full?
I'm guessing you are wishing to create a 'cocktail'? Personally i would mix the two together before adding to the carto otherwise you may get a 'layered' affect with the different flavours unless of course thats what you're looking for.