I'm thinking you may be on a secondary node if the system sounds best with the speakers toed out. It reminds me of an old system I had years ago where I needed to tip the speakers up, they sounded best there, I have now come to believe this is because they sounded badly because they were not good quality, and thus the secondary node, as created through the room was less treble, thus a better sound. I figure that is not the issue with your speakers, so I'd try a number of possitions to see if there is a second place that sounds good, start with the speakers at 90 degrees.
Also the XLO burn in disk, or some of Sereophiles early disks, had tracks of white and pink noise to help determain node locations. When I first set up my system "by the book" the listening position had a node, it was 15-20 db lower than everywhere else, that's when I started to learn about the room and it's interaction with the system.
It can take a long time, but eventually you will find magic!