After developing I usually hang it to dry in the office. It usually hangs there a couple of days before I get around to sleeving it and contact printing the negatives. I have very little trouble with the Arista EDU 100 or 400 curling, no more then my Kodak TriX anyway. I do use a glass negative carrier for my Beseler and I always tape it down when I am enlarging, but mostly to ensure maximum sharpness.

On the other hand, my Efke 25 120 certainly does have to be sleeved and flattened and it can take quite some time before it flattens out.

I am not sure if humidity has anything to do with it or whether the process of developing influences it.