Different approaches to employing weighted sum of grey gases data in line of sight solutions to the radiative transfer equation (RTE) are compared for mixtures of combustion gases and soot. Responses to variations in soot loading are analysed across configurations comprising uniform and non-uniform properties and compositions. Relative to a differential banded transmissivity solution, a weighted sum of grey gases (WSGG) solution, which solves the RTE for each grey gas component, yields greater accuracy than a total property (TP) solution. The latter evaluates radiative properties on a cell-by-cell basis for application in a single equation. However, accuracy of the TP solution is shown to improve with increasing soot loading.