G'day , J160 MTOW 540Kg.......on your numbers of 497Kg gives you 43Kg
Flight Manual says 18Kg allowable behind EACH seat to retain CofG specs, with 2x18 =36
and 43-36 =7Kg below MTOW = lunch on the laps!
Have a great trip.
C'mon guys.....this No "Laughter is the best medicine"....and shouldn't be on this forum or we end up with raising our individual necks red!
"The meek will inherit the earth.......If that's OK with you!"