I'm working with limited space and trying to figure out how much length is required to seat a person but still have room to scoot out and in. For instance, my breakfast table chairs are 18" wide where your knees bend. So is 22" per person reasonable if trying to figure out how many people can comfortably sit at an island area? In other words, to seat 3 people at the island it seems I'd need it to be close to 6 feet long. Also, what is a reasonable overhang - place-setting depth? Thank you!