I am not sure exactly how a Hammond Key click should sound as I have never owned a Hammond and only occassionally play one but agree that experimenting with a layered sound is probably the way to go. In Sound Explorer, Sound Effects group there is a Flute Key Click sound which might provide a suitable starting point. If you select this and go into Sound Edit you can tweak it to suit. I tried adding the Organ Click from Group M of the basic sounds and also a little White Noise (also from Group M). You can also adjust filtering and effects. Be sure to save your edited sound to the Sound Memory bank and then to disk or SD card. You can then assign your drawbars to Right 1 and the Key Click to Right 2. Alternatively if you wish to use both Right one and 2 for drawbar sounds, assign the Key Click sound to Part 4, and also assign the Technicord to part 4 using the octave setting and adjust part 4 level and octave to suit.

Cheers
Len C.