The wall thickness seems to be almost equal to the length of the shelf outside the room. I am not sure you can get too much radiation into the room with those dimensions.
If you are looking to push light deeper into the room you’d have to increase the width of the window aperture, reduce the length of the lightshelf inside the room and also ensure that light shelf material is reflective enough to push all the light through.
If you are using HB[+] also ensure that, the ambient divisions are sufficiently high (-ad 10000 should be enough). The value for -lw should be lower than 1/ad (…eg 0.01 if -ad is 100 and so on).