I would like to add cropping ratios to my custom products, but I am not 100% sure on the maths! I have 24 x 20 , 16 x 12, 23 x 16 and 24 x 16. I would think that a ratio of 3 to 2 would be close but any suggestions appreciated.

Why don't you put the actual ratio for each product? It doesn't have to be the same across all your products.

24 x 20 = 6:5

16 x 12 = 4:3

23 x 16 = 23:16

24 x 16 = 3:2

Hope thats what you were looking for...

Thanks Kevin, thats exactly what I was looking for. Cheers