On the long wall or short wall- Speaker set-up

I recommend you experiment, if you can, with an angled/diagonal placement,  that's neither parallel to either wall.  You can mitigate a lot of room modes in this way.  

To all, perfect advice, thank you. My intention was to allow the architect to design a couple of windows and the electrician to place the dedicated circuits in advance. I have to go before the town board for a variance that I will most assuredly receive but they ask for details. I think I have the advice I needed from an experienced community. Will report in as the project advances. 

Avoid windows if you can. Even closed they're horribly noisy. My back yard is a forest. Even so the noise coming right through the window panes tool 1/2" thick MDF panels to shut out. 

Avoid architects if you can. They charge a fortune, and love complicated expensive designs that they use to impress and distract from the fact any competent designer could do better for a fraction of the cost. Which I know, having taken competing bids from a number of them for my room. In my case the best design was also the cheapest of the six we got.

Avoid dedicated circuits, plural. You want one. One. Read the above again. If that doesn't do it, listen to Michael Fremer at 15:50
https://ultimist.com/video/2018/07/21/michael-fremers-listening-room/

As one datum point:

The dimensions of the Great Hall (Golden Hall) of the Musikverein in Vienna (the home of the Vienna Philaharmonic) are: 161’ long, by 62’ wide, by 59’ high. The Hall probably has the best acoustics in the world for symphonic music.

You could scale down the dimensions for your use, although the width vs height could be a problem.

Over the years, I’ve heard over 20 performances in the Great Hall by the VPO, and that’s what I use as a reference for my own system. Obviously, I’ll never get there, but it helps.