1st Post Intro & Ramblings

You have not helped anyone, you have provided 1/2 of the basic instructions that can be found on literally thousands of websites, blog posts, etc. Most of the good ones will start with a discussion of bass nodes and listener placement, before getting into speaker placement. That move them out from the wall, then make a triangle is not "audiophile" grade help, it is Crutchfield level (though if I remember they had a good guide at one point).  There are so many half - decent to good articles on the web that writing a few things in a forum post that are not even complete, on an audiophile website is not "helping"

Real sounds don’t come from two places at the same time, then come from one place. When you recreate them coming from two places, those locations you perceive sounds to be are artificial and hence subject to things like where you are sitting, are did you turn your head, etc. Again, the center channel locks the vocals to the screen, where the majority of dialog in a movie happens. It also focuses the sound in the center, where again, the majority of action actually occurs in movies. Real sounds come from one spot in space, which a center channel defines for the center of the screen (approximately) and that make it immune to listener position, head rotation, etc. You cannot replicate that with two speakers .... and we are not even getting into the rear channels which again, two fronts cannot recreate.

If you read my post completely, I did mention that sweet spot is limited for 1 or 2 people. If you read my posts completely I am giving the most basic advice for the masses, why? Because in all my years doing this I have seen a lot of systems that were not tuned properly. Anyone who reads what I have posted can get results. Crutchfield and the speaker manufacturers themselves all say the same thing, it is the basics. But you have still provided nothing but noise.

You have not provided the basics as you have not addressed listener placement for avoidance of bass nodes. I am not going to cover that as there are many resources that do. 

For a basis start:

https://realtraps.com/art_room-setup.htm

But to my point, you have to think about more that just rules, i.e. boundary effects can dominate:

http://arqen.com/acoustics-101/speaker-placement-boundary-interference/

Of course GIK acknowledges that preferences and room sizes, etc. come into play:

https://www.gikacoustics.com/room-setup-speaker-placement-201-part-one/

This is an audiophile community, most are looking to get well beyond the basics.

I am yet to figure out who helped who, but would like to mention that I actually like mono. Not that it is end of it all, just that it is enjoyable to me, too.

I’m glad to see you can read but apparently it escapes you. Start with post 1. 
I still say, you have not heard a properly tuned stereo or did that escape also?