On temperature and ventilation here's setup.

Grow room is one of two bedroom closets built on either side of dormer in window with knee wall slanted in back on top. Giving me just over 5'6" in height to work with. Side by side = 58" wide by 28" deep. Attached eye bolt screws into bottom of closet shelf at 5'6" and four hole (two each side) angle brackets on sides - attach these with two screws leaving two hole for running poly rope thru. This way the lamp is fixed without having to tie a knot in it as the rope pulls against itself creating traction and no slippage!

Temperature: using small thermometer; temp when left on top shelf around 90 degrees in afternoon. temp when at plant height just under lights is usually 81 or 82 (plants currently sitting on top two cement blocks on sides or 8" above floor). I believe the majority of the heat in the top of the closet is from the roof heating up in the afternoon outside being transferred in and not from the lights.

Ventilation: bottom of closet door has about a 1/4" gap and I am running a small fan on floor outside directed or blowing at the gap at bottom of door. Not the best but it is working for now. Considering adding small fan inside when I add the CFL's if needed.

Shovel - I got the idea of using the soho cups from your other posts.