1)Newer burners don't support slower speeds such as 1x.
2) Burning higher speed media at slower speeds for better quality is a complete myth. For example, burning most 4-16x media at 2x will result in poor burn quality.
While there are no hard rules, the general procedure to follow for best burn quality is to burn media at its rated speed, except 16x which will typically burn best at 12x, sometimes 8x.
3) Your favorite media, Ritek -R, has been known to give people many problems in the past 12-18 months or more. They were once considered pretty good media, but later batches of 4x and especially their 8x media has been riddled with problems. Many people have had their 8x -R media burn fine initially, only to deteriorate to unreadable levels in a matter of months.
Without getting further into details about media brands, media codes (who actually manufactures the media, as brand in itself means nothing in terms of who actually makes the media), Verbatim media is some of the best media out there and is almost always a safe bet for burning well, I suggest buying that. If it is 8x, burn at 8x. If it is 16x, burn at 12x.
P.S. - I also have that burner and, while it's not my best burner, it does a respectable job. I would suggest using the latest 'test' firmware in the Liteon forum here and using the test version of the Smartburn utility, then enabling HyperTuning, Online HyperTuning, and Smartburn. All are designed to improve burn quality. Here's the link to Smartburn - http://club.cdfreaks.com/showthread.php?t=177331
Here's the link to getting the latest test firmware for your drive (try either PV8P or the later PV8Q for your drive). http://club.cdfreaks.com/showthread.php?t=172018