For both #1 and #2, the answer is no. The plugboard sets the series_index in a copy of the book's metadata. That index is a floating point value, and can only accept floating point values. It might be possible to set it to python None (would require a python template). I strongly suspect this won't work. If it doesn't fail in the plugboard then I don't know what the device driver would do with it.
It is possible that the 2-decimal-digit limitation can be ignored, but given the number of moving parts I don't know what will happen on the device, or even if the behavior is deterministic. If this interests you then try it and see.
|