I initially started with that configuration. The primary problem is the Stops are NOT independent. They need to be turned On or Off without affecting other Stops. In your recommended approach, pressing a Stop that is off, will turn on other stops that have related subcontrols in the Combo buttons. For example, press Combo 1, it and G1 are both on. Press G3 (which should only turn G3 On and not affect any Combo or other Stops) and G2, G3, and G4 turn on along with Combo 4. I would like to set up basic organ Combo-Stop operation with MidiDesigner.