From what I see, there are examples where both 洞 and 口 can be used to describe holes in things. For example from samples in Pleco:
衣服撕了个口 (A hole was torn in the jacket)
衬衫破了一个洞 (Have a hole in one's shirt)
This being the case, what are the differences in usage between these two characters? Do these relate to different types of holes? Is one character more common than the other one for this use case?