In order for TADS video to be visible on the CPG's HDU when TADS is the selected sight, the LVL and GAIN knobs on the TEDAC must be turned up to near-max levels, which makes the TEDAC video feed too bright. Otherwise the HDU TADS video is too dim to be seen. This results in being forced to commit between using the TEDAC or the HDU to see TADS video, which should not be the case. Observed during the 30mm Gun training mission, when starting in active pause, with all displays set to night, which were the starting conditions for that mission. Steam VR mode was used.