Two surprising things I found that improved my imaging and staging...

plumptonvinyl... 50" center woofer to center woofer

@gp4jesus using ht for stereo and setting that up is beyond my pay grade.

In stereo systems, first reflection points at side walls and ceiling should be first place for room treatments. I'd suggest diffusion is best for all first reflection points, absorption will deaden the sound. Diffusion also works well for center of front wall.

Toe in and width between speakers work in concert, the further you space the speakers the more toe in is usually required. Get the ratio right and you'll attain the widest sound stage and still retain strong center image. As previously mentioned there are no hard and fast rules for speaker placement in any particular room and system. Multiple owners of any particular speaker will likely end up with speakers in different positions relative to side walls, front walls, toe in and spacing. The best advice I can give is to experiment, you may be amazed to find previously unthought of positioning may be optimum. Also, not too many rooms are perfectly symmetrical, mine being one that isn't, this requires different positioning for each speaker.

As with all parameters of sound quality, the spectrum of performance based on location and toe in is variable, and subject to highly personalized preferences. One typically cannot capture the entire range of parameters of sound quality desired and maximize them all with one setup. It is usually a preferred set of compromises. 

And it's a whole lot of fun to play with setup!  :) 

And it’s a whole lot of fun to play with setup! :)

I will not call connecting and disconnecting highly cosly amplifiers or speakers one after the other "fun" save for a reviewer perhaps...

It is more fun to reach OPTIMAL S.Q. for a chosen system in a chosen room,for my "chosen" ears, studying acoustic with information, experiments and listenings...

After all, really creating  a good setup has nothing to do with changing components each month....

But perhaps it is me who are crazy, or worst, too poor to buy all these stuff...Then in the obligation to resolve myself and my thinking to be  about  less elevated "high end" matter than a new piece of gear : acoustic...
😊

In my listening/TV room l have my two channel & 5.1 HT systems in a low console My room has vaulted ceilings and my listening position is eleven from my Maggie’s l have six feet from the center of my speakers to the side walls For critical listening l grab my tape measure and position my Maggie’s four feet from the wall and nine feet apart with slight toe in All measurements are within + - 1/8 inch and symmetrical
Typically l find this setup to give me the best
soundstage with excellent inner detail I’ve tried numerous speaker locations so don’t be afraid to experiment I have located my speakers twelve feet apart and six feet into the room and all over the map, just to hear the results and confirm if l have my speakers in the best position Now when l get real bored l start messing with my two sub woofers locations, but not too often as they weigh 100 lb’s each!