Our ship has sailed but yours has not yet. If you are going with the SMB penthouse top I would recommend asking questions about the two florescent lights they install on the top. The ones they installed in my rig were model TL-616 two tube 30 watt fixtures. There is also out there a TL-690 model that is also 30 watts and two tube BUT allow the fixture to be use as a 15 watt fixture (one tube on) or a 30 watt fixture (two tubes on). Each bulb is separately switched. I would guess that $$ was the reason they choose the 616 model but I really don't know.
Potential advantages to you of the TL-690 model:
1. You can adjust the light lumen level (high/low).
2. You have redundancy. If a bulb burns out you still have 15 watt fixture.
3. If you plan on dry camping for any period of time, you can reduce your battery drain and still have a light in that location by going to single tube mode.
Your lighting needs, cost and if they will switch it out are all factors.
Have fun.