I dilute my 36mg DV Cafe Braziliano down to 18mg using VG/AG. To make it simple, I pour my AG into an empty DV liquid bottle so that it's the same dropper as the 36mg juice I'm using. I squeeze two droppers full of juice to two droppers of AG. (Actually it's 1/2 droppers full of juice because that's all that gets sucked in when you pinch the top.) Then I add 8 drops of CB flavor concentrate. This usually gives me about 4ml of juice. My juice is a little under 18mg by the time I add the flavor.
So, to get yours to 24mg, you would do 2 droppers of 36mg to one dropper of AG (or PG). Then try adding 4 drops of flavor concentrate.