Excellent point. Newspaper is different from office paper which is way different from cardboard boxes. I use a wide variety of mixes according to the final purpose of the pc.
I think the point being made here is that pc will work with lots of variation in mix. Nothing to stress over unless you are trying to use pc in a structural situation. Since pc is normally used in thick walls the thickness usually makes up for concerns about compressive strength.
Once you start working with it, you get a real feel for how it will mix, as all paper is not created equal.
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