I personally think that Garp was above Roger during God Valley because Roger isn't in his prime yet. Even in their clash, Garp seems less damaged than Rogers. I think by the end of the God Valley, Rogers will have a Haki bloom(which happens in tough battles like Rayleigh explained), and then He will reach his prime and it will becomes Roger's era, but yet I would place Garp above Roger in Conq Haki. But "HEY IT'S JUST A THEORY, A ONE PIECE THEORY!!!!"
