In article ,
DJFawcett26 wrote:
...Depending on the amount of leg room you
allow and how much the seat is reclined,
I got about 3 feet difference in passenger
CG...

If there is a 3 ft. shift in cg with passenger mass, I suspect either your
calculations, the mass distribution analysis, or the wing placement is wrong.

Cg shifts are predicated on the overall mass distribution. If a passenger can
shift the cg 3 ft., something is wrong, especially on a two place airplane (I
am assuming this is the airplane that was on the linked website).

READING LESSON:
He said a 3 ft difference in the *passenger*cg*.
i.e. the length of the moment arm assigned to the weight of the PASSENGER.

It will have a _far_smaller_ effect on the AIRCRAFT c/g.