If he is still hunched in the morning I would call. Settling-in stool clears up on its own, a hunched hamster usually does not.

This is the best kind of build post. What mesh did you use for the lid and how did you frame it?

Check it twice a day for three days. If he starts pawing at the cheek or refuses food, that is a vet visit.

This is exactly why I tell people to be patient. Six weeks is fast, honestly.