Don't reduce the cap values in the Stereomour or Stereomour II. In general, cap values are chosen the same whatever the type. In almost all of our designs, we do not use more capacitance than necessary to get the performance we want (hum in this case).
People often try smaller capacitors in the hopes that the designer used a capacitor larger than necessary. This is called "wishful thinking". The alternative is to analyze the design yourself to see if a different value will work - hence the suggestion to use the PSUD software. This is a lot of work!