Emu authors have said that it doesn't matter what kind of games you use(PAL or NTSC) you won't see much difference between the working bios. The recommended ones are scph1001 and scph7502, but dtlh3002 works perfectly for me.
I think it only really matters with 1 or 2 games where its only a certain bios that let people play. I forget which games these are though. maybe Vagrant Story?