If you think it’s a 6 seater check the w&b. I’ve found them to be very large and comfortable 4 seaters.
Very true. The fact that there are six (or four) seats in a plane does not mean that the plane can be expected to carry that many people any distance. Two important things to remember about that: The weight of an occupant for that vintage of plane was set at 170 pounds. It is possible that your passenger(s) weigh more than that - you are responsible for knowing, and accounting for that! Not just piling in five more people, 'cause that's how many seatbelts there are. And, the certification basis for that plane also requires only that it carry all seats occupied, and fuel for one half hour of flying. The plane was never required to demonstrate all seats occupied, and full fuel (let alone bags). So, again, don't be fooled by what's written on the box, do the W&B, and don't fudge the numbers!
And, While I'm giving loading advice, yes, a plane will cruise faster/more efficiently with an aft C of G. But, if you err behind the aft limit, a stall may occur more easily, and spin recovery may become very difficult, if not impossible (I've done some testing on this). So, do the W&B!