I think the best way to reserve terminals is to draw them on the schematic. If a terminal physically exists, it should also be in the schematic.
If you ever use it, you need to update the new components in the schematic connected to the reserve terminal.
A different thing is to reserve enough space between terminal blocks if one day you need to put more terminals, but if the terminal exists, although it is not connected it must be in the schematic.
It's like connectors. If a connector has 10 pins, but only 4 are used, the other 6 should be in the schema but unconnected.
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Ok, I'll try to compile a 32bit version.