He says you should use only integer numbers in the list of custom aspect ratios, though there are real numbers used in the predefined list of aspect ratios: 2.21:1, 2.35:1 and 2.39:1. 20:21,20:22,20:23 2:2=2/2=1 2:3=2/3=0.66 So you would like to have some ratio between 1 and 0.66 You can work with ...