T5's 8-bulb versus 4-bulb

[DeanneD]

I was planning to buy two 4-bulb, 48-inch lights to hang over wire racks, but I found someone who has two 8-bulb, 48-inch light fixture, one-month old (or so he says) for a good price. Will this be too much light? My plan is to hang lights over wire shelving racks, one fixture above the rack unit and the second fixture about mid-way to the floor, underneath the first.

I have a variety of orchid types in my small collection, but of course I know I'll be adding many more plants! I have plants now from every level of light requirement, from low-light phals to high-light vandas. I don't have good natural light in my house. They're in a north-facing room in the cloudy northwest.