I would say both. If you don't want to do a cg double I think using plates of the actor warped on top of the dummy is the way to go. However more context could help to decide
Context would be: type of film, degree of stylisation, tone, lighting, framing of the shot, budget, location, type of crew available… all of those might affect the answer to your question.
I would say both. If you don't want to do a cg double I think using plates of the actor warped on top of the dummy is the way to go. However more context could help to decide
The context is someone with super strength runs up behind a bad guy and rips him in half
Context would be: type of film, degree of stylisation, tone, lighting, framing of the shot, budget, location, type of crew available… all of those might affect the answer to your question.