1. No clue but the best bet is canreef.com and look in the buy/sell part.
2. Cultured LR is always cheaper. But if it is cured you can add it all at once without a problem.
3. I would get 2/3rd of your LR up and going then you can add it in small icrements AS LONG AS IT IS CURED IT HAS TO BE CURED otherwise you will get mini amonia spikes and that isnt good for fish, pods, inverts and corals.
4. Verticle isnt always good it is hard to get corals to attatch to a verticle wall but you can use marine epoxy.
5. As for lighting it all depends on what u put in the tank. If you do SPS coral you are going to need dual 25 watt Halides and that top isnt big enough. if you do LPS you are going to need 175 watt of Halides or place your LPS corals nearer to the top. Softies you can use PC MH VHO or T-5. Log into nano-reef.com there is tons of articles on lighting. In a closed hood like that I would use PC's or T-5's becasue of the low heat also put some fans on there. 2 pushing air in and 2 pushing air out.