Unfortunately this did not work as expected.
Division.NumberOfKeys seems to be responsible for the numbers of keys drawn on the virtual console.
Division.NumberOfKeyActionNodesIfDifferentFromNumberOfKeys is responsible for the number of "speaking keys" on the virtual keyboard.
If I set Division.NumberOfKeys to 61 and Division.NumberOfKeyActionNodesIfDifferentFromNumberOfKeys to 58, I see 61 keys on the virtual keyboard, but only 58 keys are sounding. This is what I expected.
However, it did not work the other way around (Division.NumberOfKeys = 58 and Division.NumberOfKeyActionNodesIfDifferentFromNumberOfKeys = 61)
The virtual keyboard has 58 keys (expected), but there were only 58 sounding keys (unexpected).
BTW: I loaded ranks and stops with 61 NumberOfPipes and MappedDivisionKeys.
Chris