If the fight was at 154 as GGG said he'll fight Floyd at 154, I could see Floyd walking GGG down and stopping him late on. #EasyWork
If the fight were at 154, it would not be the optimal weight for GGG, obviously. He may be so drained that I have to give Mayweather the slight advantage. Only GGG knows how debilitating getting down to 154 would be for him. Official prediction would still be GGG by TKO, probably in round 3 or 4.
Floyd usually employ that style when his opponent is a southpaw and lack of punching power. He is unwilling to do that with a smaller Pac. He won't do that with the bigger, traditional stance GGG. I see GGG traps him in the corner and beat him up.
GGG needs to go out stomp out Canelo, then unify the division. He would be the top guy in boxing. Call out the old man. Offer him the chance at becoming undisputed middleweight champ. Give the old man a rehydration clause that he won't come into the ring more than 160 or whatever. Then crush him.