Since I always watch the trilogy with either headphones or a soundbar, I’d choose the 35mm stereo mix. If you’re watching with just your TV’s internal speakers, the difference between the stereo and surround wouldn’t be very noticeable, so you can pick either one. The six-track audio is ideal, but without a surround system, it just downmixes the audio and isn’t any better than the stereo track. As for any content differences, the stereo and surround are basically the same. Only the channel mixing is different.