On recent form you'd have to favour cueball head, in all honesty.
Going 12 with Alvarez and Brook despite losing both is superior to being extended by Curtis Woodhouse (and losing several rounds) and being unable to do anything at all with Young Mutley.The same one who lost every round against Brook?
I think it's a pretty even fight. I'd slightly favour the fresher Gavin, but Matt's experience will certainly test him.