The process to make an extra seat.
Roll over bar and rear seat frame - here we have the beginnings of the rollover bar which bolts to frame #5 and the aft end which will have a tube connecting the top of the rollover bar to a bracket on frame #8.
The rear seat frame mount is being fabricated to bolt to the rear bulkhead plate and a mock up of the seat frame with an original seat is being trial fitted.
Very nice WW2 pilot seat!