Jeff, to water by the weight of the plant and their baskets, that is called " hefting the pot" and that is also how I learned to gauge when to water. ( although the mini Phal I keep right now, is mounted)
At a visit to Germany, we saw many beautiful Phals ( sold everywhere cheaply) growing on windowsills. Many Germans have lace curtains in front of their windows, which provide perfect conditions/perfect light.
Jeff, I should add after reading that you water from the top, that one might want to make sure the crown of the plant is dry by the end the day, many Phals are lost due to crown rot. If there is water standing in the crown after watering, it is easily soaked up in a corner of a paper towel. These plant grow tilted in nature, so the rain water doesn't collect in the crown, but drains easily.