Hi OGauge,
For me it depends on the exact car. I put more people in the rear observation cars on the sofa and chairs, dining cars, bar/lounges cars and upper domes areas. Less people go in the Pullman sleeping cars. My reasoning is most people don't want to spend a cross country trip in a little roomette or cramped open section seat staring at a total stranger. So, I make sure my people are out of the sleeping cars, moving around and doing things on the train.
Dome seating
Main dining area
Sleeping car with roomettes and bedrooms
Bar/Lounge
I don't know the percentage, but I always leave some empty seats in the busy sections.
