Fish length question

Hey all! Had a quick question about fish surfboards that I couldn't quite figure out. Here goes: Now we all know that the fish design is unique because while generally (apart from when the surf gets humongous) longer boards work in smaller surf, smaller boards in larger surf, the fish defies that completely. I understand that is due to its volume, lack of rocker, and overall shape. I also understand that the short length makes fishes more maneuverable. My question is: what's going to be harder to ride in steep, 5 ft surf: A 5'4 fish, or a 5'10 fish? Basically, the longer the fish is, does that make it more stable or less stable in big waves? Because I understand its issue with steep waves is the lack of rocker, so technically wouldn't a smaller fish be better for the bigger stuff because it could handle steeper drops without its nose catching?