As a rule you want to be on the ball of your foot. Of course, like anything else, a good rider will be adjusting these things as they need to be adjusted. Riding in the wet, breaking hard, mono-hopping, etc will all call for slight adjustments in foot placement.
Primarily you need to find what is most effective and/or most comfortable and make the too merge harmoniously.
As a rule you want to be on the ball of your foot. Of course, like anything else, a good rider will be adjusting these things as they need to be adjusted. Riding in the wet, breaking hard, mono-hopping, etc will all call for slight adjustments in foot placement.
Primarily you need to find what is most effective and/or most comfortable and make the too merge harmoniously.
Peace