Hi Liz, Since I have been growing for over 25 years I have found that the 4' fixture is best for my plants and also the most economical. When I was working and could afford them I used Varilux bulbs which I found gave the plants a great growth rate, however, they are expensive and cost retail over 12 dollars each. Since retiring I switched to 40 watt cool whites which I purchase by the box at Home Depot or Lowes. They work well and give me no problems. I have on occassion in the past used Gro-Lux and Gro-Lux WS. Both bulbs give good growth to the plants and make the plants look really beautiful and healthy under the light. But when you remove the plant from the light into natural light there is great disappointment. They loose their color and look rather ordinary. The Gro-Lux WS bulbs were always cheaper than the Gro-Lux. Many people prefer to use one cool whit and one warm white to grow. Since I cannot find warm whites I now use cool whites exclusively. Hope this helps. Fred in NJ

I think if you have the lights above the mirrors, that centered above them and should be smaller than the mirrors. Pointing up or down seems to be no wrong or right, simply a matter of personal preference. I think sometimes it depends on the light itself, some look better pointing up aand some look better pointing down. ( I have in my master bath two 3 light vanity lights pointing up above my mirrors, In my hall bath, I have a 3 light one pointing down. I like them both.I guess I was no help other than to say the light should be less wide than the mirrors.

I'd opt for shorter lights that wouldn't require a truck mounted boom lift to service.

Update: I was wrong about our house windows. They are not TDL but FDL (full divided light), which for Andersen windows means interior and exterior permanent grilles, with an aluminum spacer bar between the glass. This seems to be the same thing as Simpson SDL. Any reason not to buy 3/4 light wood doors from Simpson that are SDL? The only other thing I've learned is that with a Simpson SDL door, if glass breaks, it may be cost-prohibitive to replace the glass, and necessary to replace the whole door. With TDL, an individual broken light can be replaced. Any thoughts on which doors will look better, and what makes the most sense? Attached are photos that show what the TDL and SDL lights look like in the Simpson doors. The light with the dark framing is the TDL and the one with the aluminum piece between the glass is the SDL.