I ended up taking the aluminum foil off the reflector. I found some self-adhesive "chrome" at a hobby shop, and used that to back the reflector. I can't tell the difference, but I feel better about it.
The canopy is simply a 1"x6" frame with a 1"x2" glued along the inside vertically. The 1x2 is what sits on the tank trim, and the shoplight sits on top of the 1x2 (thus the 1.5" height above the tank). Then I just glued in some standoffs which the top will sit on, when I find a top. I wanted to get some dark tinted plexiglass, which I thought would look neat. But I may just use a sheet of masonite, since that is easy to find. The pic isn't very detailed as far as canopy construction, but it's something.