Here's a small app for mac users for making incremental backups of Maschine Plus SD cards. BackupMaschine works like MacOS Time Machine: only modified files are actually stored. This allows to save disk and to keep all snapshots distinct, so you can easily restore any of them.
Backups are kept under user's Documents/Maschine-Backup folder
Just place the app on SD card root and launch it whenever you want a backup.