I keep a word doc list and a Pinterest page - and freely admit that I am not as organized about keeping track of everything as I should be.
I do wish the ATP data base listed height of plant and the ADS specifications.
I went from 30 different dahlias to 64 last year, and have close to doubled that again this year. At 30 plants I could remember what I needed to know, at 60 I think I remember(?), at 125, I know I'll have to get more organized.
I am liking using Pinterest - most of the Dahlias I added were already "pinned", so easy to get good images, but until I grow them I don't know how tall they will be.