Regarding the questions about which 480 positions should be used:
Rather than thinking of 2 sets of 480 positions, perhaps it's better to think of 480 sets of 2 positions. The two positions in each set are related by left-right reflection, and have equivalent strategy trees.
I agree with John that it's aesthetically preferable to play all 960 positions, but if you want to choose just one from each pair, how about the one where the Queen is to the left of the King in White's starting position?
Rather than thinking of 2 sets of 480 positions, perhaps it's better to think of 480 sets of 2 positions. The two positions in each set are related by left-right reflection, and have equivalent strategy trees.
I agree with John that it's aesthetically preferable to play all 960 positions, but if you want to choose just one from each pair, how about the one where the Queen is to the left of the King in White's starting position?