Thanks for the input (including everybody in the previous posts) this is all helpful. 250 watts is easy peasy.

I will say I have no interest in dome tweeters. Every competitor I am looking at for my dedicated room is an HE speaker with a compression driver and waive guide, i.e., JBL Pro, JTR, etc. I want big dynamic sound in my dedicated room, which will be 100% movie viewing.

The main reason I am even considering the Sierra Towers is because I have become very fond of my Sierra 2s in my living room, and thought 3 Sierra Towers with the Lunas, for example, for surround and Atmos duty would be pretty sweet. I am 100% sure that set up would sound like butter most of the time. Really my only concern is output and dynamic peaks when I want to let her rip. I do not want to run into thermal compression at reference or over-tax the speakers at reference, because I will want to run it that loud occasionally.

Its just hard to know for sure how much is enough headroom until its all in the room. I really am not into ordering and returning speakers, so I'd like to get it right the first try.