1 DVD+R media will be more compatible
2 Verbatim is one of the best branded media out there (amazon tends to have them for good prices)
3 almost every system out there will use the laser more to read backup media compared to original media, the beter the media used the less risk of laser damage
4 alot of Slim users find DVD-DL/DVD9 discs don't read very well compared to DVD/DVD5 disc's (if needs be dig out DVD5 rips if you find out a game you want was on a DL/DVD9 disc)
5 burn at the lowest speed your burner can, to help ensure quality burns
basicly anything that the PS2 struggled to read including scratched original will give the laser strain
if you want a guide for media look at
http://www.videohelp.com/dvdmedia this also includes console compat