Weddingbee boards

I'm not sure about sites to use. I tried to make my own seating chart using rectangle tables. I figure not everyone is the same size. If a place setting area and elbow room require about 36" wide and you need 18" for the chair itself pulled out and seated then you also want room behind a seated person for some one to pass. So I left 2' from the back of the chair to either the wall, or center of the aisle. So the tables I have back to back there would still be a 4' space between the chairs pulled out to 18' on both sides. I know I'm pretty small, so I can squeeze between some small spaces, but I'm considering the larger people I'll be inviting to the wedding. Also, if you are having serving staff you want enough room for them to pass while carrying dirty dishes and what not. So maybe 3' would be better for against a wall.