Just from aside:
Generally:
It is important to understand that
light has to work together with materials to get desirable effect. You can spend hours tweaking lamps/lights and still end up frustrated with uneven lit scene. Effects such as light fixture glow should be set in the end, when you first manage to fill the scene with light and get rid of deep black shadows (behind the wc) and burn outs (on the floor).
Particulary:
I would start with pairs of lightcone down + lightcone up with 130 deg cone angle each and falloff around 1 to fill the room with even ilumination. Than you will see that some of your materials are burn out (like floor for example) and you might want to decrease "diffuse" and "ambient" in
matte materials
or balance "roughness" and "specular" in
reflective materials
.
Finally, after looking for some light-fixture-glow-solution I found (thanx to Dwight) that "Wall light indirect" with "diffuse light" on is something you should try, but as I said before: only after you fill the scene with light
and balace your materials. For light emmiting part of light fixture use "constant" or "dielectric" shader with high "transmitance".
Below examples show the result.
You might also want to check this topic as there is something about the light fixture as well.
http://archicad-talk.graphisoft.com/viewtopic.php?t=10074&postdays=0&postorder=desc&&start=30
Hope this helps,
Cheers