Sculpt open or closed mouth first for creatures

I'm sculpting a dragon character and need some advice. When I sculpt humans, I would typically sculpt the mouth closed, with perhaps a small bit of separation of the lips, then add a mouth box. However, with the character I am currently working on, I am unsure if that is the best way to go. I want to do a few renders with different expressions, and the mouth needs to part more like that of a crocodile. I think sculpting the jaw muscles may be tougher if the mouth is closed, but doing it that way could also help my rotational proportions. What workflow is recommended in this case?