I currently have a 7.1 setup with 3x CMT-340 LCR (the LR speakers are on TP-24 pedestal stands and the center is horizontal below the TV) and 4x CBM-170 Surrounds.

I am moving into a new house soon with a dedicated theater room. I'm currently trying to brainstorm and plan out what I want to do with the room. My current plan is to build a faux wall with an acoustically transparent screen, and then have the LCR speakers hidden behind the screen. I also want to expand the system to a 7.2.4 Atmos system.

Having a front soundstage behind the screen gives you the opportunity to have 3 identical speakers for LCR instead of the normal setup where you have matching LR speakers and a different center. On that note, what I'd like to do is buy a single TP-24 pedastal for the center speaker and have all 3 LCR vertical. Are there any technical differences between the CMT-340 center and the mains, or is the center actually identical to the mains if you turn it vertical? Would I need to rotate a tweeter or something? Is it possible to special order a single pedestal or do they have to be ordered in pairs?

For Atmos speakers to go with my current system, is the recommended approach to mount 4 HTM-200s to the ceiling?

Also, if down the line I want to upgrade to a Sierra system I'd probably want to have 3 Sierra Towers for the LCR front soundstage. So a similar question: Is it possible to special order a single Sierra Tower, or do they have to be ordered in pairs?

Thanks.