The lack of bright dome lighting is prototypical. Though coach domes were generally not extra fare, the railroads had the good sense not to over-illuminate them. Having ridden the MILW, GN and CB&Q domes, it is my recollection that there was theater type floor lighting for the same reasons. Having just finished a project to modify a MTH Super Dome, I replicated that lighting effect by drilling holes in the floor of the dome, in the aisle adjacent to every other seat, to admit light from the illuminated area below. With room lights dimmed or extinguished, the effect is quite realistic - there is a glow from the dome but no Klieg Lights. Perhaps that compromise would work for you, too.
One of my favorite memories is of watching a huge, violent thunderstorm roll across the prairie at twilight from the single dome of the homely little "Aksarben Zephyr". Such an experience would not have been possible with bright overhead lighting.