Actually, ITU recommendations for 7 or more speakers allow the side surrounds to be positioned as far forward as 60 degrees from the median line, as opposed to Dolby's 90-110 degrees. There is actually good psychoacoustic evidence to support the ITU recommendations, particularly the ear's sensitivity to reflections from the 60 degree angle increasing the perception of spaciousness and envelopment. Floyd Toole himself combines the ITU recs into his own composite recommendations in his book "Sound Reproduction." This is also why Tomlinson Holman, when discussing going beyond 5.1 in his book "Surround Sound", starts with adding a pair of wide front speakers.
To the original poster, your original setup is better than your 6.1 one. Two extremely knowledgeable and experienced professionals go beyond the recommendations from Dolby and posters here. I think that 7.1 would be better than 5.1 for more listeners watching your corner setup. Why not try it and see?