Paper: hexagon with a side length of 10.5 cm / diameter of 21 cm
Model: hexagon with a side length of 5.5 cm / diameter of 11 cm
Today I received the e-copy of Alessandro Beber's new book and I of course had to try it out immediately. After practicing just the background (as he suggests), I grabbed another sheet of Elephant Hide and attempted his first exercise featuring a simple 3-D cube illusion. This is the result. It's by far not as clean as Alessandro's folds, but does prove that his book and accompanying videos clearly explain how to fold his projects.
And, yes, these are time-consuming! Yet the result is so worth it. :)