Awesome, that is good news and really opens up my choices!!
Just to be clear, the sequence would be:
1. Mount clips and hat channel
2. wire and install backer boxes
3. Mark location on floor where light should go w/ plumb bob
4. Drywall and GG
5. Cut the hole using plum bob/floor marks, wire and mount the light as you described
Also, what is the current best practice for backer boxes? Are you
) adding a flange to the box then gluing/screwing them to the first layer of OSB or drywall; or
) skipping the flange and just gluing/caulking them in position while gravity holds it in place?
I've seen pictures of both and wasn't sure what is recommended...
Thanks a ton! I really appreciate all the advice from these forums.