Agreed, NA will be easier to start with. On the Mefi 3, Timing and Fuel tables were very straight forward, those are an easy fix. Some of the tables are very arcane and require a significant amount of research and/or knowledge.
I suspect that the Mefi 1 is a simpler ECU all around. Using Scanner Pro (also in the Mefi Burn package) to watch the engine diagnostics while underway is interesting and enlightening.
The DynoJet is a fantastic device and likely in my future even with a great running boat.
R277

In the MEFI controllers the file that is loaded into the computer is a fixed size. Only a certain amount of space in the file is allocated for each data item. In the MEFI1 file the BPW vs. MAP/RPM table is 14 rows x 5 columns of 16 bit data. That means the table is allocated 14 x 5 = 70 spaces of 16 bit data or 140 bytes. This table starts at address 0xB633. The next table in the MEFI1 is the Voltage Compensation vs Battery Voltage and it starts at 0xB6BF. 0xB6BF – 0xB633 = 0x8C or 140 bytes. There is only 140 bytes allocated for this table which means that the number of rows and columns is not saved in the computer.

If you increase the number of rows and/or columns in the BPW table you will just overwrite the data in an another existing table.

Changing the number of rows and columns probably will not harm the computer, but you will not get the results that you expect.