mantloko, I understand that blank media in South Africa is very expensive. If you want to be safe, burn the media at its rated speed or one tick lower. Burn 8x rated media at 8x, 16x rated at 12x or 8x.
Taiyo Yuden makes media under the brand Fujifilm (+R/-R), Sony (+R), TDK (+R/-R), Verbatim pastels, Thats and more. They all must show Made in Japan. You can check the media ID with DVD Identifier.