Don't follow 'fashion'! Just do what works and feels best for you. For free ride and slalom, having 30+cm apart gives you more stability and control because you can slide the hook back and forward a bit to help balance gusts and lulls. The most important bit is to get the line fixing points in the best place for overall balance so neither arm is being overworked and you can fully load the sail without arm strain.
This works for me:
