This does not directly address your question, but I initially used a B35 for my first child, and that lasted about a day. Forgive me if you have other children and have still decided this will work for you, but I find it 100% mandatory to have a shoulder carry (or cross body) diaper bag because you will be carrying your baby in both arms as well as anything else you can possibly fit in your hands while still holding the baby…like your keys to lock the door, the bottle etc you grabbed at the last minute. However, to answer the question, I would go for B35, as larger sizes are more likely to soften (without enough wear that could compromise the bag) and for a soft and lighter leather, I think swift/gulliver would be a good bet. Togo or clemence are not out of the question and can get smooshy. Vintage Ardennes is gorgeous but a bit thicker and heavier. The very light leathers do not tend to get smooshy (Box, VN, Chevre, Epsom), and when they appear to be, they are often damaged. I would not do HAC 32 because then you are limited even more by the smaller handles. When you say B32, I am not sure if you are thinking B30 or B35. For me B30 is a wonderful size, but a small tote with a limit to its capacity of about what you would bring out to dinner or to the office. I like that B35 can fit enough for a day out and about.