I have the 42” and the 16”. There are times that I wish the 16 was a 21 (weeknights when cooking for 5-6 and the 16 is a bit small). Below is the 42 with the center split set up - you can flex the width quite a bit. I prefer this to splitting left or right side for most cooks. I typically only split to the side when smoking brisket, pork, etc.
Hope this helps