I am a firm believer that extreme toe in with full range driver speakers in enhances/widens the soundstage
Welcome and I agree! (With a caveat.)
Am running 16 year old Bob Brines (retired) FTA-2000 that Fostex F200a drivers (8 inch, no whizzer, AlNiCo magnet, rated 30-20,000 Hz at 8 ohms, 89 dB/w/m, $575 each when last available) in floor standing Martin King inspired transmission line cabinets. Had Bud Purvine (inventor) add EnABL treatments. Duke LeJeune suggested adding "Late Ceiling Splash" tweeters (Dayton Audio 1 1/8 inch soft domes in parallel with a capacitor). The tweeters sit on the floor directly behind the speakers aimed upwards. Reading Floyd Toole's "Sound Reproduction" convinced me to add 3 carefully placed subs in my 8ft x 13ft x 21ft room to address inherent in-room bass peaks/dips (in a mid-field setup).
Speakers are 5.5ft from front wall, 2ft from side walls, 9ft apart, 7ft from listening position, toed-in to cross 2ft in front of listening position. Center stage imaging is maintained while high frequencies are enhanced thanks to the tweeters. Soundstage is enlarged compared to a equilateral speaker/listening position setup while maintaining image specificity. Note that I also have ten GIK 2ft x 4ft 244 absorption panels at front, side, and rear wall first reflection points. Also have three tall randomly filled bookcases at midpoint of side walls. And use <500 Hz version of Dirac.
BTW the same setup is recommended for controlled directivity designed speakers. And single drivers are in effect wave guides so also follow controlled directivity thinking to some degree.
