The best test in your own room with your own system is your own ears. Although I find that bromide quite irritating, it's true. But there are tools to help one calibrate. My speakers sound best with no toe in at all, according to the manufacturer, but my room is not a Rorschach pattern. That is to say there is no right/left symmetry. Nor is my hearing equal in both ears.
The best tool I've found is the Isotek set up CD.
http://fatwyre.com/isotek-ultimate-system-setup-cd
https://www.musicdirect.com/accessories/IsoTek---Ultimate-System-Set-Up-Disc-CD
After using the CD, My soundstage is wider, higher, deeper and more precise. It took a few hours, but I wound up with my speakers CLOSER to the front wall and toed-in very slightly and my listening chair moved closer. The first time I used it, the CD led me to have my Left speaker toed OUT slightly and the Right toed in severely. It sounded a lot better than before; but it didn't sit well with me so I used the CD to help me arrange furniture and then the speakers again. Now it sounds even better. I re-use the CD every time things change in the room.
The best tool I've found is the Isotek set up CD.
http://fatwyre.com/isotek-ultimate-system-setup-cd
https://www.musicdirect.com/accessories/IsoTek---Ultimate-System-Set-Up-Disc-CD
After using the CD, My soundstage is wider, higher, deeper and more precise. It took a few hours, but I wound up with my speakers CLOSER to the front wall and toed-in very slightly and my listening chair moved closer. The first time I used it, the CD led me to have my Left speaker toed OUT slightly and the Right toed in severely. It sounded a lot better than before; but it didn't sit well with me so I used the CD to help me arrange furniture and then the speakers again. Now it sounds even better. I re-use the CD every time things change in the room.