Until recently we routinely cooked for a family of 5 (3 big eaters + me & my wife) on a 22 Performer. Never had any problem with cooking real estate for steak, chicken burgers or fish. I think you will be just fine with a 22 OTG and its a really great versatile cooker.
PS: I upgraded to the 26.75 OTG when my son moved out and took his Performer with him and really like cooking on it.
Weber 26.75 OTG w/CI grates & SJ/WSM Mini
Home built 24"x72" reverse flow stick burner trailer with 18"x44" grill w/CI grates and upright SS gas oven/smoker.
Home built 48" fire pit with a 30"x30" Santa Maria style ranch grill.
Home built lump charcoal retort, iGrill & a bunch of other cooking toys.