You don't have to manually delete files. You can use specialized software to "sieve" a full collection into a 1G1R set. 1. Choose Your Tools Incoming Redump Hearto's 1G1R PS1 collection : r/Roms
Storage Efficiency: Trimming a PS1 or PS2 Redump set can save hundreds of gigabytes by removing duplicate data found in "PAL" and "NTSC" versions of the same title. 1g1r redump sony playstation
Accuracy: Redump tracks hashes (checksums) to ensure your file is a bit-perfect copy of the original retail disc. Understanding 1g1r and Redumping
If you tell me more about what you're looking for, I can help further: The technical steps to create your own 1G1R set? You don't have to manually delete files