I didn't have like that rounded shape leaves but first leaves of my plants were fat too. Its usual with young plants. Probably about the strain or maybe connected with other conditions, I'm not sure.
And yes, usually older fat leaves are much more droopy than youngsters. It's not easy for them to raise up easily I think.

I didn't try spraying that often. Just did several times in a week to increase humidity level in cabinet. Don't know, maybe thats the reason why they're too droopy. And water on them can cause damages if you don't raise the light after spray. Try to not do until you see some movements on them. Since the soil is wet enough and humidity is acceptable, you don't need to do that often IMO.