I have been wanting this. Seems logical now that many users have/use many different devices.
The Template is save by device
IMHO this probably should be stored with (and be part of?) the device driver settings (by calibre ID? for cases of multiples of the same model)
Connect to folder is always Main
Save to Disk is a Path
Connect to device is by device:
For CC it is always Main
For a K4NT it can only be Main
Hanlin V5 (AstakPP) either