Use good quality media to preserve the life, so it isn't retrying to read sectors as much
That will matter wayyy more than your burn speed.
For PS2 like I do now, i would just use Ritek media with oxinol dye or verbatim, whichever you can get your hands on. Games are replaceable, and Ritek really cleaned up it's poo in recent years. Done some very good low error burns on the ritek media. I personally would categorise it as an upper-middle disk. Not for Archival critical master usage, but not bad for a duplication copy, or an additional copy or a game!
If you have verbatim media, your set.
For 16x media, I burn at 12x with my burner for verbatim, and 8x for Ritek F16 media (sony branded currently). Burn speed is not as critical as it was in the CD-Days. 8x or 4x is a 'safe' speed for both of these media. If you really want, test your burns with nero disc speed.
You may depending on the age of your PS2 need to calibrate the laser power (especially the 3XXXX series) to read copied disks better.
I had no problems with my old PS2 reading RW discs even after i did a calibration, which I used to use to backup games that I was likely to get bored of later, thus erasing the disc later. The laser lens on that lasted me years... I would not advise using RW disks, though.