The "refresh" button randomises as much as it can, but you can prevent a section from being randomised by "locking" it (clicking on the tiny lock icon).
So you can pick a size, lock it and hit "refresh" as much as you wish. I'm glad that you like the app, cheers!
So you can pick a size, lock it and hit "refresh" as much as you wish. I'm glad that you like the app, cheers!