Wow - those look great! But did you do the measurements to make sure those are at your first reflection points?
And, just out of curiosity, what acoustic absorption material did you use?
You may want to consider doing a 'super chunk' style acoustic treatments in the corners. There is an easy way to find out if you'd benefit: Go stand in the corner and if the bass is significantly louder than where you sit they would be helpful. I did it in mine and noticed a very large improvement in the quality of the bass. The bass volume was significantly more even across frequencies and it removed all of the rattling I was getting. It also improved the experienced volume levels at non-optimal seating positions with no increase in volume settings at the receiver or sub.
Basically you cut triangles of the acoustic material and lay them on top of each other - typically in a frame and then wrap it with acoustically transparent fabric. They can get pretty expensive if you use Owens Corning 703 type material but I used mineral wool and I want to say it cost around $50 a corner floor to ceiling. It was more of a pain to work with as its very loose, fibrous and itchy (so mask + gloves + long sleeves) but it took less than a day to do all three of my corners (stupid door is in the fourth)
Also - very very cool!