I went on the hunt for 2 captain’s chairs with a different color/look and more fabric than the side chairs. The depth of the seat should allow clearance from the front of the seat to the back of the occupant’s legs. The width of the seat tapers from the front to the back to allow clearance for legs and clothes in the front while offering elbow room at the back.
Chair seat occupant
For an updated look, make the captain’s chairs (head of the table chairs) match but have them be different from your side chairs like mine below. Here are a few more chairs that are somewhat similar to mine in shape and style but obviously different than my chairs.
In addition we would have to put one side chair some place else when not being used, and there was no good spot we could think of that would make it look not out of place.
If the seat is too deep, it will press against the occupant legs forcing them to sit away from the back or slouch forward. The seat should slant slightly toward the back to offer relaxed seating and to keep the occupant from slipping out of the chair.