I purchased my HTM-200SE's to use as ceiling-mounted atmos/height speakers. I wasn't sure exactly how I'd do it - but eventually settled on a solution, which I think worked out well... and so I thought I'd share it, in case anyone else is considering doing this.
My ceiling height is a little under 8 feet - which initially led me to the HTM-200SE's, since they can be oriented horizontally. I picked the Mount-It! Low Profile speaker mount as my starting point. The problem there is that the 200SE's mounting holes don't line up with the Mount-It! bracket, or literally any other bracket that I could possibility find. The side-squeeze mounts (like the ones recommended for the 200s) won't work on the ceiling, or at least I wouldn't trust a mount like that to hold.
So I needed a way to interface the speaker with the mount. I found an option, called a mending plate, which is a furniture bracket. The one I bought was 8" long with an M6 center slot, which was long enough to attach to the HTM-200SE and fit the M6 screw holes that come with the speaker.
The bracket wouldn't fit flush against the speaker, as the other (speaker) side of the bracket also needed screws so it would attach to the Mount-It!. I purchased M6 washers, and put 3 of them on the speaker side to act as stand-offs. Then, with M6x1x20mm screws and M6 wing nuts, I married the Mount-It! and the speaker through the mending plate.
In the end, the top edge of the speakers is less than 2" from the ceiling, and they're oriented horizontally - making it as low profile as I could get, without actually putting speakers in the ceiling. (I have a low slope roof with HVAC overhead, so in-ceiling wouldn't quite work out correctly, as I wanted the Dolby-recommended placement locations for a 5.1.2 system).
The only downside is that the accessory hardware (mending plate, M6 screws, and wing nuts) ended up costing more than the Mount-It's... and you end up with a lot of leftovers. But it was worth it to me, because I ended up with the speaker I wanted, in the location it needed to be, inside a room that I had no choice but to live with.
Some photos:
https://imgur.com/a/VrzY7ZA
I'm not trying to sell anything here - except the idea of using the HTM-200SE's on the ceiling, I guess. But if interested, here's the stuff I used:
Mount-It! https://www.amazon.com/Mount-Anti-Th.../dp/B00CSA2Y18
8.5" slotted mending plates https://www.amazon.com/dp/B09L7QD66X
M6 screws https://www.amazon.com/dp/B0BZ3X3J74
M6 wing nuts https://www.amazon.com/dp/B07QB5N4WL
M6 wing washers https://www.amazon.com/dp/B09N8T9B8F