I think we all have the same quandary. I chose to set it correctly for the front row. That makes the surrounds in front of the back row, but that does not seem to matter.
I really had no option but to get them high, and I would recommend that so they do not get obstructed. I think it helps that I have rears and surrounds. Also it so happens that the speakers I had handy for the surrounds have a 15 degree downward tilt because of the crossover configuration.
People do not complain of localizing to the surrounds, and I don't find it a problem sitting in the back row.
You can see one surround and a rear here.
You can see the other surround here.
And now I bet your curious about the fronts!