I simply copied the games to my PC using QCAM, after installing SD2vita and a 128GB memory card I copied the games back the same way.
Don't make a whole memory card backup since it will delete any newer files from your hacked vita since it will do a full memory card restore, just make regular game backups.
It was a lot easier and faster than trying to FTP 30GB of data for me (copying files via vitashell USB sometimes doesn't show all of the files, even having "show hidden files and folders" enabled on windows for me) I don't know why no one adds this in their tutorials instead of suggesting people to back up their whole ux0 folders via ftp when setting up SD2VITA.