Hi Doron,

The numbering in sound explorer gives the MIDI patch number for the particular sound. In your example of String Duo, MSB=32, LSB=6 and Patch No.=43. This is required when you wish to select sounds on the keyboard from an external MIDI controller.

The Custom Panel Mode screen refers to the manner in which the Custom Panel Button is used to select keyboard parameters. In Panel Memory Mode it selects only those parameters normally associated with a panel memory location. All Panel Mode sets up the complete keyboard including parameters which are not normally actioned via panel memory selection e.g. Music Style Arranger, and Intros.
The Custom Panel button is associated with its own unique Panel Memory which is saved in the same manner as other panel memories (press and hold Set and simultaneously press the Custom Panel button). Note that this will wipe the factory custom panel setting.

Cheers
Len C.