The skin pack is marked 1.6L (it's smaller than the one for the Eclipse Cab, btw). I plan to address whether it's "18 liters of juice, plus 1.6 liters of skins"; or, "16 liters of juice with 1.6 liters of skins," when I pour into the primary. The box and the video both say, "18 liters."
So, an objective test should answer this one:
Measure out 1.25 gallons of water. Use a half gallon for the bentonite. Pour the bag of juice and the remaining .75 gallons of water into the primary. Then I can see how much it really is. If it's at the line, then the answer is "18 liter bag." But, if I need another half gallon, then the answer is "16 liter bag."
Let us know the results if you haven't started the kit yet.
The printing on the box is misleading, it may say 18L (I thought it'd say 16L) but the reality is that you get 16L of juice.
The only kits that I know have 18L of juice plus the skins pack is the RJS En Premier, if I remember correctly, and that is a maybe.