sorry mate, firstly, I hate paint, I will do it though, more importantly though, I need more detailed schematics.
Where is the window in your picture?
Where is the door in your picture?
Can you drill holes in the walls / ceilings.

If you start with 100 plants, you will need different lighting, as I dont think you can lower the hps low enough to provide ample light needed for seedlings, also, from my experience seedlings work better with lower light, things like "mini fluros" or fluro tubes are better.
Nutrients: Don't know.
HPS lights that ship continental:
http://www.growshopalien.com/onlineshop/
I got my HPS from them, also the ballast apparently operates MH and HPS!