Priorities
Up to V3.x the priorities of the sections where fixed. With version 4 you have a free hand.
USBDLM always checks from [DriveLetters1] to [DriveLetters99] and finally [DriveLetters].
The first section that fits to the drive is used (only this one). So configure from the special cases upwards to the more general.
If the drive got the letter of a network share, then USBDLM remounts it to the next available letter.
No need no configure anything for this function. If no letter is available then the drive is unmounted.
Finally, if the drive has no mount point at all, USBDLM mounts it to the next available letter if there is one.