t5 distance question, pleae

[VickiC]

Hi,
This is a carry-over question from a question that I asked you a few weeks ago. After getting your responses from my question to you then and measuring a little more since then, we decided to use 2-4 bulb t5 fixtures...each fixture generating about 20,000 footcandles.

Referring back, my husband has helped me fix up an adjoining room to our garage (which was at one time his electronics shop) for an orchid room for me. The room is approx. 10'x10' with 2 main shelves and some "odds and ends" growing space. The ceiling is approx. 10'. The rough measurement from the ceiling to the top shelf is approx. 6' (I think...keeping in mind that a female is doing the measuring lol) The distance from the top shelf to the lower shelf is approx. 2'. Of course, the lights will be side by side...the length of the shelves. My question to you is: about what distance would you suggest that the lights be suspended from the ceiling down to above the top shelf giving the orchids on that shelf a good amount of light but also shining a sufficient amount of light down to the bottom shelf. My plans are to grow mainly dens and catts (a few Vandas) on the top shelf, and probably some phals, as well as few other different orchids, on the lower shelf. The electrician(s) should be coming tomorrow to do the installation, so I would really appreciate your advice sometime today or tonight, if poss.
Thanks in advance,
Vicki