The quickest way is to use pfsshell (Playstation File System Shell) and writing your own batch file. And yes, they need to go into the ART folder in the +OPL partition (which shows up in uLaunchELF as just OPL -- no "+" symbol).
PSX games need to go into a partition named __.POPS (that's two underscores, a periond, followed by POPS in all caps). You will need to use uLaunchELF (navigate to the MISC folder and find HddManager) to create this partition. Again pfsshell (along with a batch file) will be the fastest way.