i think "moderate near-field listening" does not have much to do with room size, specially when the room is large.
so, my instinct says it could be more than enough.
near-field means less power demands.

near-field listening in a large room means you have more direct sound than reflected sound. how much more depends on the ratio between room acoustics/size relative to the distance from the front speakers to your ears.

it would be a good thing if you specify what this means:"I listen at about 1/2 of reference level"
is it -10 or -6 or -3 dB?