I am trying different mediums with bag seed. From normal soil, soil mixed with river sand, organic potting soil, potting soil mixed with dry compost-peat-vermiculite & some rock dust. The mediums that are heavy & don't drain very well, I drill excess holes in the pots, at the sides & open up the ones at the bottom.
As for watering I wait for the leaves to droop slightly & then water until the water drips out from the bottom. Normally good for about 10 days for me as it's cold now.