I heard that bbws and ssbbws are in a weight limit cat. Like 170-350 bbw but anything over 350 is ssbbw. But I have also heard that ssbbw is over 400lbs. But most guys like the smaller bbws like 200's.
It's not all about size for me. It's about confidence and the way you carry yourself. Take the comedian Mo'Nique. I'd probably view her as "ehh" when she first started. But as she became more and more confident and proud of herself, the more and more sexy she became. So I'd say it's not so much about weight, but about the whole package (for me, at least)