All right, time to bring things up to date. It won't take too long, even though it's been three months.
Essentially what happened: When I finished the double drywall on the walls, I had to decide whether or not I wanted to double drywall the ceiling. Remember, I've got a complex existing ceiling with a soffit and light shelf. It's lots of fiddly drywall work to do it right.
Finally I decided to bite the bullet and do it right. I bought a drywall lift and a bunch of drywall for the ceiling. So far so good.
Unfortunately, double-drywalling the ceiling finally forced the issue of lighting that I had been procrastinating. Did I want cans with light boxes (cans without light boxes would defeat the purpose of double drywalling the ceiling). Could I get away with sconces and no ceiling light? Would I regret it later? Yada yada yada. Of course, this was an aesthetic decision with no way to gather hard data, so I stalled.
While I was stalled, I went ahead and built my bass trap over the entryway. It's shape is dictated by the available space in the attic above, after ripping out a bunch of unnecessary framing:
Then I made incremental progress, finding things I could do that didn't require a final decision on cans/sconces. I ripped out the light switches by the door (I'll have a grafik-eye eventually). I ripped out all the old cans and patched their holes in the drywall.
Then, finally, in mid-January I got fed up with myself and decided that if I didn't do cans in light boxed, I might regret it later. If I spent the work on the light boxes, it might be wasted, but I wouldn't regret it.
So away we go. I've built four of the five light boxes and am ready to install them. (The fifth one goes way back in the attic where I need to crawl in. I want to make sure the first four work before I crawl in and measure for the fifth).
The boxes are pretty big: 14″ x 10″ x 10″. They are made following the general ideas from here:
How to build a soundproof fireproof light box
. They are basically boxes made out of 3/4″ MDF, glued and finish nailed together, with a 6″ hole in the bottom and a 5/8″ hole for the flex-conduit/wire to come out the side. The insides (except the bottom where the light hole will be) are lined with hardiplank/green-glue. This will give more heat resistance than straight MDF. The green-glue will (hopefully) give a bit less sound transmission. Mostly, the green-glue can't hurt.
The boxes are sized to fit exactly between the studs on top of the existing drywall. I plan to drill a pilot hole from below to mark the spot where I want the boxes to be. I'll place the boxes from above over those holes. I'll attach the boxes by screwing through the studs from the sides (so I can remove the boxes later if I ever want to modify them), then caulk all around.
The flex-conduit from each lamp exits the box through a small hole in the side (not shown in the pictures) and goes to a metal junction box on the outside. That'll make wiring up easy. If I kept the junction boxes inside the light-box I would have code problems (not allowed to bury' a j-box).
I bought 6 cans for $30 at HD, but ended up not using them. Instead, I stripped down the original cans I removed from the ceiling. Those were higher build quality and seemed less likely to rattle. If anybody wants 6 cheap IC can lights, let me know.
I'm hoping to get some installed soon, but time is tight these days
Here are the light boxes (I've since green-glued/caulked them and added the can and the junction box. They are a lot less pretty now...)