I find it difficult to get a comfortable 3 finger grip on the CS9, fingers are all on but barely. The 457 has plenty of space for 3 fingers. It is also thinner with stock plastic grips than the CS9 with the stock rubber grips. I have Hogue rubber grips on my 457 and find that feels right.
The frontstrap to backstrap distance is were I notice the biggest difference in feel. On 9mm pistols my hand wraps around the grip, on .45 pistols my hand is 'reaching' a little. Kind of like the difference between a round handle on a broom vs a squared handle on a hockey stick, ( if that makes any sense ). Both useable but different.
The 457 is like the bigger brother of the CS9 but not too big. It is about the largest sized pistol I would want carry concealed regularly. The 3913 is my favorite.
CS9 = small, 3913 = medium, 457 = large (relative to each other).
The 457 shoots nice and mine is a keeper. Probably worth the 4 hour drive.
I could measure up my 457 if that would help.