It turns out that I was not wrong calculating the 1:10 ratio because I learned the ratios shown on the drawings from post 11 are backwards!
So the 1:10 ratio is actually 2:1 (like I figured out) and the other ratios 1:2, 1:3, 1:4, 1:6 are actually 10:1, 6:1, 4:1, 3:1.