You're talking about large, but I already said Pica's golem will be a lot smaller on marineford. He only has one building to work with. So it would be more like small giant size.The difference is that the floor isn't being thrown towards him. At Impel Down, Inazuma stuck his swords into the stationary ground, then started running and cutting. If Golem Pica's arm is aiming at him, he isn't going to be able to do that unless his scissors are large enough to cover Pica's fist, and since Golem Pica's arm contains streets on it, I find that unlikely.
Also instead of running across the floor cutting it when Pica smashes he can just stick out his scissors when he evades and let Pica bring the movement.