How heavy are the walls?
By level: 3.5 pt for Very easy, 2.25 pt for Easy, 1.5 pt for Medium, 1 pt for Hard, 0.9 pt for Expert and 0.75 pt for Extreme, never under KDP's 0.75 pt. The Crayon look draws heavier walls. The solutions keep 0.75 pt or more even when drawn smaller.