It's a purely visual/aesthetic thing. I think having them line up with each other tends to look best, but that's just me. If you think having them on opposite sides looks better, or is easier to use (turn on/off), then that's cool too. Although if you don't have something like the QR coupler that can spin freely, you may need something in the middle of them to make them fully tightened in the proper position relative to eachother.
Well...... My Doublesaber has v2 hilts...... So I don't know if a quick release coupler will fit my saberstaff. My Saberstaff has no sound.