Actually, just don't burn them at a too low speed.
Originally Posted by socius
The rule to burn your discs at a lower speed than the maximum allowed only applied to disc burners that are unable to burn discs reliably at higher speeds.
Update your burner's firmware too, in order to get the best out of your burner.
Also, not all Verbatim DVD-Rs are good.
Only those manufactured by Mitsubishi (MCC002 and MCC003) and Taiyo Yuden (TYG02 and TYG03) are good.
There are some that are manufactured by CMC Magnetics, and those are not too good for PS2s.
SCPH-10000 S. MINOKAMO v1.01 (Defunct)
SCPH-10000 S. KISARAZU v1.00 (faulty)
SCPH-15000 S. KOHDA (With warranty seal!) :D
DESR-5100 S. EMCS