The other "HOWTO" thread was meant more for how to get started. This one I'm hoping will funnel away some of the application of Sysex - which is different from just being able to use the mechanism and follow the data list.
The latest from the other thread was the observance that H/M/L address of 00/7F/00 seems to be reported back from a bulk dump but is not documented. I have a Montage, not MODX - but my experiments have shown:
addr of 00/7F/00 parameter read returns 01 as a single byte of data.
addr of 00/7F/01 parameter read returns 00 as a single byte of data
addr of 00/7F/02 parameter read returns 00 as a single byte of data
addr of 00/7F/03 parameter read returns 00 as a single byte of data
addr for L>03 and H/M=00/7F seems to be invalid (keyboard error messages).
Trying to write to all 4 of the above bytes does not cause an error - but does not seem to change anything. Data read back is still the same as before parameter change. Conclusion/guess is that these registers are read-only. Meaning is unknown. Possible this is a flag (00/7F/00) for debug build vs. production build. That's a wild guess. I don't think there is much of interest you can do with this/these bytes.