I installed regular 2x2 studs in the ceiling with nail plugs. Then I ran flex conduit in a loop corresponding to the spotlights' placement. I installed drywall panels (smaller and easier to work with). I fed the power from a junction box via the ceiling box to a transformer (with your surface, you might need a few of these, just place them close to the spotlights' holes).
Then I just plastered the seams as usual a few times. After the first painting, you can clearly see any irregularities. Then it's just a matter of plastering again. Along the edges, I used latex caulk.
