We used 1.5 cups of light DME for our ~5 gal batch. I used "Simply Apple" apple juice, but people on here have used the cheapest cheap juice and it turned out fine.
HOWEVER, I feel like our bottles are not carbonating and I have a hypothesis. I know that you don't make starters with refined sugar because after a few generations of eating simple and easy to process sugars like glucose and fructose, yeast lose the ability to process maltose. So, after we fermented the apple juice we put in 1.5 cups light DME (which is what we typically do for any 5 gal batch fermented to completion) but I don't think the yeasties are biting, perhaps due to this loss of the ability to ferment maltose. Any opinions? Similar experiences?
If I may make a suggestion for priming - use more apple juice to prime instead of DME. I use 1.5 cups of sugar in a pint of water, so check the "serving size" for the mass of sugar per unit apple juice serving and calculate whatever is appropriate. Or, use refined sugar for your priming sugar. I think these will be safer options, and you don't really have to worry about picking up some sort of "cidery" flavor from the sugar.