This...would be nasty. For extra giggles, add 1920's gloves, rules, and refs (goodbye, neutral corner rule!)
Greb should be favoured, but Calzaghe has a nasty style for him and is bigger. 1 - Greb is probably more skilled at making the opponent lead. 2 - Greb is the more proven in terms of heart.
Never even seen you on the claassic before and now you do a load of them about the same bloke in one day!
I think the 1920s gloves would make Calzaghes position impossible due to his hands. Expect him to have a Jimmy Braddock type resume with a lot of losses fighting in this era.