Tianjin Airlines A321-200

Only in density: this fit carries an extra row of economy, and is otherwise the same shape, from the exit-door legroom rows to the rear galley. If you have a choice, the lower-density fit is marginally gentler, but the seat advice carries over.

At the mid-cabin exit doors if legroom matters, in the forward third if you value calm and a fast exit. The far rear is the compromise: galley, lavatories and the longest walk off a very long aircraft.

Three worth knowing: seats directly ahead of an exit may not recline fully, the door boxes intrude into foot space at some window positions, and a couple of window seats at the doors have no window. The map notes flag each one.