Lower Cargo Hold Seating
Worldways of Canada bought two ex-PSA L-1011 and had them converted for charter work at Eastern's Contract Maintenance Service in Miami. They had forward cargo-hold seating and a stair to the main deck. Worldways did not want to sell those seat. They would be unoccupied during takeoff and landing so we were able to remove some 1,200 lbs of heavy belly plating installed to protect lower deck passengers in the event of a belly landing. There were a couple of windows I dimly remember. Due to hull curvature the pax looked through almost a tunnel to see through them.
There's a big weight penalty for seating passengers near the outside belly skin.
Never did hear how Worldways faired operating those two Tristar aircraft. They would certainly have been a lot harder to maintain than their DC-8.