I have a large toadstool that I’ve grown from around a inch in size now it’s 7-8” across and it stays flat doesn’t wrinkle like others I see why is this.
I don't really think there is an answer. All these things are alive and do what they do. I have 1 that stays mostly flat. 1 that is ruffly. 1 that is growing like an ice cream cone. May be flow, may be light. You could experiment with flow easy enough.