From my experience, if you allow the boot installtion of Batocera to create the shared partition, it will automatically create a EXT4 partition. To use your own preferred NTFS partition you should format it before booting and label it RECALBOX but dont add any files to the partition.
Next open recalbox-boot.conf which is on the boot partition and change the line:
Next boot should create the recalbox folder structure automatically for you. I use this on a dual boot disk with Windows XP and Batocera booting from Grub4Dos from the boot.ini file.
The Batocera install image requries a minimum of 2GB for the boot partition and at least another 2GB for the shared partition which can be on the smae drive or an external USB drive. Adding the modified line above to the recalbox-boot.conf file will allow you to use both internal and external drives for the shared disk. I don't know why this recalbox-boot.conf file isn't documented more in detail as it fixes many black screen issues.