Black cdr's
I had figured that the type of cdr really should not make a difference, just that some people in the binary cd games newsgroups swear by the black ones but since I don't have a bootdisc or have modded my ps1 I can't really say but you are right about trying to mod a game console, I think from my research the safest way is to use a bootdisc as then about the only thing that physically touches the console is the piece of tape used on the bit that tells the console that the lid is open.