Lighting My Orchid Cave

[Gareth]

What formula do I use for how many grow lights and what kind I need for a 7' long x 6' high x 5' deep growing chamber i.e. (orchidarium)?

My plan is to have this chamber for orchids demanding more light. I want to use big lights, or as big as would be required. The chamber will house as many orchids as practical using shelving. Low light orchids will be in a different grow chamber.

Thanks for helping me design what I call my orchid cave.