I agree Golovkin is a clear favourite.

Proksa has had bad luck with promoters and he had to wait a couple of years for the EBU title shot. (The British commentator said he was "protected" - despite the fact that Proksa never fought at home)
No wonder Proksa now takes whatever they throw at him, without the time for a proper camp. IMHO Eddie Hearn doesn't care. It's not like Proksa has a following the UK.