Questions about putting up tongue-and-groove on ceiling
My partner and I removed some old gross (but asbestos-free!) ceiling tiles from a downstairs room, and we were hoping to replace them with some tongue-and-groove planks. We were looking at the Armstrong track/plank system, but the only variety we were interested in was ugly in-person so the new plan is staining our own planks, assuming we could securely nail those into sufficiently thick plywood. However, there are existing 1"x4" planks going in the same direction we'd want the new planks to go and a weird bit of framing that protrudes into the room in one corner, so my options to keep a flat ceiling and not mess with that framing seem to be the following (to my relatively layman dumdum eyes):
1. Put thinner plywood over the 1x4s, nail planks to that (assuming that's feasible) * Pros: easy, straightforward * Cons: some lost ceiling height, not sure what thickness plywood I'd need or if the whole thing would sag/turn bad in a couple years 2. Remove all the 1x4s the ceiling tiles were stapled to, replace with 1" plywood to be level with that bit of framing. * Pros: nails go into floor joists/thick plywood * Cons: that stuff is expensive 3. Screw 1" boards along floor joists to be level with framing, put thin plywood on that, then plank. * Pros: cheaper than 1" plywood, nails go into wood/joist * Cons: is just screwing a board to the bottom of a joist even a thing, or would it look like a hack job?
Image link of current ceiling state and that weird bit of corner framing (I'd remove the staples and crud before attaching anything to the 1"x4"s, of course): https://imgur.com/a/bgzqRna